1.useRequest #

• useRequest是一个强大的异步数据管理的 Hooks，React 项目中的网络请求场景使用 useRequest 就够了
• useRequest 通过插件式组织代码，核心代码极其简单，并且可以很方便的扩展出更高级的功能。目前已有能力包括：
  • 自动请求/手动请求
  • 轮询
  • 防抖
  • 节流
  • 屏幕聚焦重新请求
  • 错误重试
  • loading delay
  • SWR(stale-while-revalidate)重新请求的同时使用过期数据
  • 缓存

1.1 API #

const {
  loading,
  data,
  error,
  params,
  run,
  runAsync,
  refresh,
  refreshAsync,
  mutate,
  cancel
  } = useRequest(service,
  {
    manual,
    defaultParams,
    onBefore,
    onSuccess,
    onError,
    onFinally
  }
);

1.2 结果 #

参数	说明
data	service 返回的数据
error	service 抛出的异常
loading	service 是否正在执行
params	当次执行的 service 的参数数组
run	手动触发 service 执行
runAsync	与 run 用法一致，但返回的是 Promise，需要自行处理异常
refresh	使用上一次的 params，重新调用 run
refreshAsync	使用上一次的 params，重新调用 runAsync
mutate	直接修改 data
cancel	取消当前正在进行的请求

1.3 选项 #

参数	说明
manual	默认 false。 即在初始化时自动执行 service
defaultParams	首次默认执行时，传递给 service 的参数
onBefore	service 执行前触发
onSuccess	service resolve 时触发
onError	service reject 时触发
onFinally	service 执行完成时触发

1.4 安装 #

npm install ahooks  --save

1.5 依赖Hooks #

• useRequest是一个强大的异步数据管理的 Hooks，React项目中的网络请求场景使用 useRequest 就够了
• useUpdateEffect用法等同于 useEffect，但是会忽略首次执行，只在依赖更新时执行
• useCreation 是 useMemo 或 useRef 的替代品
• useLatest返回当前最新值的 Hook，可以避免闭包问题
• useMemoizedFn是持久化 function 的 Hook，理论上，可以使用 useMemoizedFn 完全代替 useCallback
• useMount是只在组件初始化时执行的 Hook
• useUnmount是在组件卸载（unmount）时执行的 Hook。
• useUpdate会返回一个函数，调用该函数会强制组件重新渲染

2.自动请求 #

• 默认情况下，useRequest 第一个参数是一个异步函数，在组件初始化时，会自动执行该异步函数。同时自动管理该异步函数的 loading , data, error 等状态。

2.1 src\index.js #

src\index.js

import React from 'react';
import ReactDOM from 'react-dom/client';
import App from './App';
const root = ReactDOM.createRoot(document.getElementById('root'));
root.render(<App />);

2.2 App.js #

src\App.js

import { useRequest } from './ahooks';
import React from 'react';

function getName() {
  return new Promise((resolve) => {
    setTimeout(() => {
      resolve('zhufeng');
    }, 1000);
  });
}

function App() {
  const { data, loading } = useRequest(getName);
  if (loading) {
    return <div>加载中...</div>;
  }
  return <div>用户名: {data}</div>;
};
export default App;

2.3 ahooks\index.js #

src\ahooks\index.js

import useRequest from './useRequest';
export {
  useRequest
}

2.4 useRequest\index.js #

src\ahooks\useRequest\index.js

import useRequest from './src/useRequest';
export default useRequest;

2.5 useRequest.js #

src\ahooks\useRequest\src\useRequest.js

import useRequestImplement from './useRequestImplement';
function useRequest(service) {
  return useRequestImplement(service);
}
export default useRequest;

2.6 useRequestImplement.js #

src\ahooks\useRequest\src\useRequestImplement.js

import useLatest from '../../useLatest';
import useUpdate from '../../useUpdate';
import useCreation from '../../useCreation';
import useMount from '../../useMount';
import Fetch from './Fetch';
function useRequestImplement(service) {
  const serviceRef = useLatest(service);
  const update = useUpdate();
  const fetchInstance = useCreation(() => {
    return new Fetch(serviceRef, update);
  }, []);
  useMount(() => {
    fetchInstance.run();
  });
  return {
    loading: fetchInstance.state.loading,
    data: fetchInstance.state.data
  };
}
export default useRequestImplement;

2.7 useLatest\index.js #

• useLatest返回当前最新值的 Hook，可以避免闭包问题

src\ahooks\useLatest\index.js

import { useRef } from 'react';

function useLatest(value) {
  const ref = useRef(value);
  ref.current = value;
  return ref;
}

export default useLatest;

2.8 useUpdate\index.js #

• useUpdate会返回一个函数，调用该函数会强制组件重新渲染

src\ahooks\useUpdate\index.js

import { useCallback, useState } from 'react';
const useUpdate = () => {
  const [, setState] = useState({});
  return useCallback(() => setState({}), []);
};
export default useUpdate;

2.9 useCreation\index.js #

• useCreation 是 useMemo 或 useRef 的替代品
• 因为 useMemo 不能保证被 memo 的值一定不会被重计算，而 useCreation 可以保证这一点

src\ahooks\useCreation\index.js

import { useRef } from 'react';
import depsAreSame from '../utils/depsAreSame';
export default function useCreation(factory, deps) {
  const { current } = useRef({
    deps,
    obj: undefined,
    initialized: false
  });
  if (current.initialized === false || !depsAreSame(current.deps, deps)) {
    current.deps = deps;
    current.obj = factory();
    current.initialized = true;
  }
  return current.obj;
}

2.10 depsAreSame.js #

src\ahooks\utils\depsAreSame.js

export default function depsAreSame(oldDeps, deps) {
  if (oldDeps === deps) return true;
  for (let i = 0; i < oldDeps.length; i++) {
    if (!Object.is(oldDeps[i], deps[i])) return false;
  }
  return true;
}

2.11 useMount\index.js #

• useMount是只在组件初始化时执行的 Hook src\ahooks\useMount\index.js

  import { useEffect } from 'react';
  const useMount = fn => {
  useEffect(() => {
    fn?.();
  }, []);
  };
  export default useMount;

2.12 Fetch.js #

src\ahooks\useRequest\src\Fetch.js

class Fetch {
  constructor(serviceRef, subscribe) {
    this.serviceRef = serviceRef;
    this.subscribe = subscribe;
    this.state = { loading: false, data: undefined };
  }
  setState = (s = {}) => {
    this.state = { ...this.state, ...s };
    this.subscribe();
  }
  runAsync = async () => {
    this.setState({ loading: true });
    const res = await this.serviceRef.current();
    this.setState({ loading: false, data: res });
  }
  run = () => {
    this.runAsync();
  }
}
export default Fetch;

3.错误处理 #

3.1 src\App.js #

src\App.js

import { useRequest } from './ahooks';
import React from 'react';

function getName() {
  return new Promise((resolve, reject) => {
    setTimeout(() => {
-     resolve('zhufeng');
+     reject(new Error('获取用户名失败'));
    }, 1000);
  });
}

function App() {
+ const { data, loading, error } = useRequest(getName);
  if (loading) {
    return <div>加载中...</div>;
  }
+ if (error) {
+   return <div>加载失败</div>;
+ }
  return <div>用户名: {data}</div>;
};
export default App;

3.2 useRequestImplement.js #

src\ahooks\useRequest\src\useRequestImplement.js

import useCreation from '../../useCreation';
import useLatest from '../../useLatest';
import useMount from '../../useMount';
import useUpdate from '../../useUpdate';
import Fetch from './Fetch';
function useRequestImplement(service) {
  const serviceRef = useLatest(service);
  const update = useUpdate();
  const fetchInstance = useCreation(() => {
    return new Fetch(serviceRef, update);
  }, []);
  useMount(() => {
    fetchInstance.run();
  });
  return {
    loading: fetchInstance.state.loading,
    data: fetchInstance.state.data,
+   error: fetchInstance.state.error
  };
}

export default useRequestImplement;

3.3 Fetch.js #

src\ahooks\useRequest\src\Fetch.js

class Fetch {
  constructor(serviceRef, subscribe) {
    this.serviceRef = serviceRef;
    this.subscribe = subscribe;
+   this.state = { loading: false, data: undefined, error: undefined };
  }
  setState = (s = {}) => {
    this.state = { ...this.state, ...s };
    this.subscribe();
  }
  runAsync = async () => {
    this.setState({ loading: true });
+   try {
      const res = await this.serviceRef.current();
+     this.setState({ loading: false, data: res, error: undefined });
+   } catch (error) {
+     this.setState({ loading: false, error });
+   }
  }
  run = () => {
    this.runAsync();
  }
}
export default Fetch;

4.手工触发 #

• 手工触发
• 如果设置了 options.manual = true，则 useRequest 不会默认执行，需要通过 run 或者 runAsync 来触发执行
• run 与 runAsync 的区别在于：
  • run 是一个普通的同步函数，我们会自动捕获异常，你可以通过 options.onError 来处理异常时的行为
  • runAsync 是一个返回 Promise 的异步函数，如果使用 runAsync 来调用，则意味着你需要自己捕获异常

4.1 src\App.js #

src\App.js

import { useRequest } from './ahooks';
import React from 'react';

function getName() {
  return new Promise((resolve, reject) => {
    setTimeout(() => {
      //resolve('zhufeng');
      reject(new Error('获取用户名失败'));
    }, 1000);
  });
}

function App() {
+ const { data, loading, error, run, runAsync } = useRequest(getName, {
+   manual: true,
+   /* onError(error) {
+     console.error('onError', error);
+   } */
+ });
+ return (
+   <>
+     <button disabled={loading} onClick={run}>
+       {loading ? '获取中......' : 'run'}
+     </button>
+     <button disabled={loading} onClick={runAsync}>
+       {loading ? '获取中......' : 'runAsync'}
+     </button>
+     {data && <div>用户名: {data}</div>}
+   </>
  )
};
export default App;

4.2 useRequest.js #

src\ahooks\useRequest\src\useRequest.js

import useRequestImplement from './useRequestImplement';
+function useRequest(service, options = {}) {
+ return useRequestImplement(service, options);
}
export default useRequest;

4.3 useRequestImplement.js #

src\ahooks\useRequest\src\useRequestImplement.js

import useCreation from '../../useCreation';
import useLatest from '../../useLatest';
import useMount from '../../useMount';
import useUpdate from '../../useUpdate';
import Fetch from './Fetch';
+import useMemoizedFn from '../../useMemoizedFn';
function useRequestImplement(service, options = {}) {
+ const { manual = false, ...rest } = options;
+ const fetchOptions = { manual, ...rest };
  const serviceRef = useLatest(service);
  const update = useUpdate();
  const fetchInstance = useCreation(() => {
+    return new Fetch(serviceRef, fetchOptions, update);
  }, []);
  useMount(() => {
+   if (!manual) {
      fetchInstance.run();
+   }
  });
  return {
    loading: fetchInstance.state.loading,
    data: fetchInstance.state.data,
    error: fetchInstance.state.error,
+   run: useMemoizedFn(fetchInstance.run.bind(fetchInstance)),
+   runAsync: useMemoizedFn(fetchInstance.runAsync.bind(fetchInstance))
  };
}
export default useRequestImplement;

4.4 useMemoizedFn\index.js #

• useMemoizedFn是持久化 function 的 Hook，理论上，可以使用 useMemoizedFn 完全代替 useCallback

src\ahooks\useMemoizedFn\index.js

import { useMemo, useRef } from 'react';
function useMemoizedFn(fn) {
  const fnRef = useRef(fn);
  fnRef.current = useMemo(() => fn, [fn]);
  const memoizedFn = useRef();
  if (!memoizedFn.current) {
    memoizedFn.current = function (...args) {
      return fnRef.current.apply(this, args);
    };
  }
  return memoizedFn.current;
}
export default useMemoizedFn;

4.5 Fetch.js #

src\ahooks\useRequest\src\Fetch.js

class Fetch {
+ constructor(serviceRef, options, subscribe) {
    this.serviceRef = serviceRef;
+   this.options = options;
    this.subscribe = subscribe;
    this.state = { loading: false, data: undefined, error: undefined };
  }
  setState = (s = {}) => {
    this.state = { ...this.state, ...s };
    this.subscribe();
  }
  runAsync = async () => {
    this.setState({ loading: true });
    try {
      const res = await this.serviceRef.current();
      this.setState({ loading: false, data: res, error: undefined });
    } catch (error) {
      this.setState({ loading: false, error });
+     this.options.onError?.(error);
+     throw error;
    }
  }
  run = () => {
+   this.runAsync().catch(error => {
+     if (!this.options.onError) {
+       console.error(error);
+     }
+   });
  }
}
export default Fetch;

5.传递参数 #

5.1 src\App.js #

src\App.js

import { useRequest } from './ahooks';
import React from 'react';

+function getName(xing) {
  return new Promise((resolve, reject) => {
    setTimeout(() => {
+     resolve(xing + '三');
      //reject(new Error('获取用户名失败'));
    }, 1000);
  });
}

function App() {
  const { data, loading, error, run, runAsync } = useRequest(getName, {
    manual: false,
    defaultParams: ['张']
    /* onError(error) {
      console.error('onError', error);
    } */
  });
  return (
    <>
+     <button disabled={loading} onClick={() => run('赵')}>
        {loading ? '获取中......' : 'run'}
      </button>
+     <button disabled={loading} onClick={() => runAsync('钱')}>
        {loading ? '获取中......' : 'runAsync'}
      </button>
      {data && <div>用户名: {data}</div>}
    </>
  )
};
export default App;

5.2 useRequestImplement.js #

src\ahooks\useRequest\src\useRequestImplement.js

import useCreation from '../../useCreation';
import useLatest from '../../useLatest';
import useMount from '../../useMount';
import useUpdate from '../../useUpdate';
import Fetch from './Fetch';
import useMemoizedFn from '../../useMemoizedFn';
function useRequestImplement(service, options = {}) {
  const { manual = false, ...rest } = options;
  const fetchOptions = { manual, ...rest };
  const serviceRef = useLatest(service);
  const update = useUpdate();
  const fetchInstance = useCreation(() => {
    return new Fetch(serviceRef, fetchOptions, update);
  }, []);
  useMount(() => {
    if (!manual) {
+     const params = fetchInstance.state.params || options.defaultParams || [];
+     fetchInstance.run(...params);
    }
  });
  return {
    loading: fetchInstance.state.loading,
    data: fetchInstance.state.data,
    error: fetchInstance.state.error,
    run: useMemoizedFn(fetchInstance.run.bind(fetchInstance)),
    runAsync: useMemoizedFn(fetchInstance.runAsync.bind(fetchInstance))
  };
}

export default useRequestImplement;

5.3 Fetch.js #

src\ahooks\useRequest\src\Fetch.js

class Fetch {
  constructor(serviceRef, options, subscribe) {
    this.serviceRef = serviceRef;
    this.options = options;
    this.subscribe = subscribe;
+   this.state = { loading: false, data: undefined, error: undefined, params: undefined };
  }
  setState = (s = {}) => {
    this.state = { ...this.state, ...s };
    this.subscribe();
  }
+ runAsync = async (...params) => {
+   this.setState({ loading: true, params });
    try {
+     const res = await this.serviceRef.current(...params);
+     this.setState({ loading: false, data: res, error: undefined, params });
    } catch (error) {
+     this.setState({ loading: false, error, params });
+     this.options.onError?.(error, params);
      throw error;
    }
  }
+ run = (...params) => {
+   this.runAsync(...params).catch(error => {
      if (!this.options.onError) {
        console.error(error);
      }
    });
  }
}
export default Fetch;

6.生命周期 #

• useRequest 提供了以下几个生命周期配置项，供你在异步函数的不同阶段做一些处理
  • onBefore：请求之前触发
  • onSuccess：请求成功触发
  • onError：请求失败触发
  • onFinally：请求完成触发

6.1 src\App.js #

src\App.js

import React, { useState } from 'react';
import { useRequest } from './ahooks';
+let success = true;
function getName(userId) {
  return new Promise((resolve, reject) => {
    setTimeout(() => {
+     if (success) {
+       resolve(`name${userId}`);
+     } else {
+       reject(new Error('获取用户名失败'));
+     }
      success = !success;
    }, 1000);
  });
}
+const initialUserId = '1';
function App() {
+ const [userId, setUserId] = useState(initialUserId);
  const { data, loading, error, run, runAsync } = useRequest(getName, {
    manual: false,
+   defaultParams: [initialUserId],
+   onBefore: (params) => {
+     console.info(`开始请求: ${params[0]}`);
+   },
+   onSuccess: (result, params) => {
+     console.info(`请求成功:获取${params[0]}对应的用户名成功:${result}"!`);
+   },
+   onError: (error) => {
+     console.error(`请求失败:${error.message}"!`);
+   },
+   onFinally: (params, result, error) => {
+     console.info(`请求完成`);
+   },
  });
  return (
    <>
+     <input
+       onChange={(event) => setUserId(event.target.value)}
+       value={userId}
+       placeholder="请输入用户ID"
+     />
+     <button disabled={loading} onClick={() => run(userId)}>
        {loading ? '获取中......' : 'run'}
      </button>
      {data && <div>用户名: {data}</div>}
    </>
  )
};
export default App;

6.2 Fetch.js #

src\ahooks\useRequest\src\Fetch.js

class Fetch {
  constructor(serviceRef, options, subscribe) {
    this.serviceRef = serviceRef;
    this.options = options;
    this.subscribe = subscribe;
    this.state = { loading: false, data: undefined, error: undefined, params: undefined };
  }
  setState = (s = {}) => {
    this.state = { ...this.state, ...s };
    this.subscribe();
  }
  runAsync = async (...params) => {
    this.setState({ loading: true, params });
+   this.options.onBefore?.(params);
    try {
      const res = await this.serviceRef.current(...params);
      this.setState({ loading: false, data: res, error: undefined, params });
+     this.options.onSuccess?.(res, params);
+     this.options.onFinally?.(params, res, undefined);
    } catch (error) {
      this.setState({ loading: false, error, params });
+     this.options.onError?.(error, params);
+     this.options.onFinally?.(params, undefined, error);
      throw error;
    }
  }
  run = (...params) => {
    this.runAsync(...params).catch(error => {
      if (!this.options.onError) {
        console.error(error);
      }
    });
  }
}
export default Fetch;

7.刷新(重复上一次请求) #

• useRequest 提供了 refresh 和 refreshAsync 方法，使我们可以使用上一次的参数，重新发起请求

7.1 src\App.js #

src\App.js

import React, { useState } from 'react';
import { useRequest } from './ahooks';
let success = true;
function getName(userId) {
  return new Promise((resolve, reject) => {
    setTimeout(() => {
      if (success) {
        resolve(`name${userId}`);
      } else {
        reject(new Error('获取用户名失败'));
      }
      success = !success;
    }, 1000);
  });
}
const initialUserId = '1';
function App() {
  const [userId, setUserId] = useState(initialUserId);
+ const { data, loading, error, run, runAsync, refresh, refreshAsync } = useRequest(getName, {
    manual: false,
    defaultParams: [initialUserId],
    onBefore: (params) => {
      console.info(`开始请求: ${params[0]}`);
    },
    onSuccess: (result, params) => {
      console.info(`请求成功:获取${params[0]}对应的用户名成功:${result}"!`);
    },
    onError: (error) => {
      console.error(`请求失败:${error.message}"!`);
    },
    onFinally: (params, result, error) => {
      console.info(`请求完成`);
    },
  });
  return (
    <>
      <input
        onChange={(event) => setUserId(event.target.value)}
        value={userId}
        placeholder="请输入用户ID"
      />
      <button disabled={loading} onClick={() => run(userId)}>
        {loading ? '获取中......' : 'run'}
      </button>
+     <button onClick={refresh} >
+       refresh
+     </button>
+     <button onClick={refreshAsync} >
+       refreshAsync
+     </button>
      {data && <div>用户名: {data}</div>}
    </>
  )
};
export default App;

7.2 useRequestImplement.js #

src\ahooks\useRequest\src\useRequestImplement.js

import useCreation from '../../useCreation';
import useLatest from '../../useLatest';
import useMount from '../../useMount';
import useUpdate from '../../useUpdate';
import Fetch from './Fetch';
import useMemoizedFn from '../../useMemoizedFn';
function useRequestImplement(service, options = {}) {
  const { manual = false, ...rest } = options;
  const fetchOptions = { manual, ...rest };
  const serviceRef = useLatest(service);
  const update = useUpdate();
  const fetchInstance = useCreation(() => {
    return new Fetch(serviceRef, fetchOptions, update);
  }, []);
  useMount(() => {
    if (!manual) {
      const params = fetchInstance.state.params || options.defaultParams || [];
      fetchInstance.run(...params);
    }
  });
  return {
    loading: fetchInstance.state.loading,
    data: fetchInstance.state.data,
    error: fetchInstance.state.error,
    run: useMemoizedFn(fetchInstance.run.bind(fetchInstance)),
    runAsync: useMemoizedFn(fetchInstance.runAsync.bind(fetchInstance)),
+   refresh: useMemoizedFn(fetchInstance.refresh.bind(fetchInstance)),
+   refreshAsync: useMemoizedFn(fetchInstance.refreshAsync.bind(fetchInstance))
  };
}
export default useRequestImplement;

7.3 Fetch.js #

src\ahooks\useRequest\src\Fetch.js

class Fetch {
  constructor(serviceRef, options, subscribe) {
    this.serviceRef = serviceRef;
    this.options = options;
    this.subscribe = subscribe;
    this.state = { loading: false, data: undefined, error: undefined, params: undefined };
  }
  setState = (s = {}) => {
    this.state = { ...this.state, ...s };
    this.subscribe();
  }
  runAsync = async (...params) => {
    this.setState({ loading: true, params });
    this.options.onBefore?.(params);
    try {
      const res = await this.serviceRef.current(...params);
      this.setState({ loading: false, data: res, error: undefined, params });
      this.options.onSuccess?.(res, params);
      this.options.onFinally?.(params, res, undefined);
    } catch (error) {
      this.setState({ loading: false, error, params });
      this.options.onError?.(error, params);
      this.options.onFinally?.(params, undefined, error);
      throw error;
    }
  }
  run = (...params) => {
    this.runAsync(...params).catch(error => {
      if (!this.options.onError) {
        console.error(error);
      }
    });
  }
+ refresh() {
+   this.run(...(this.state.params || []));
+ }
+ refreshAsync() {
+   return this.runAsync(...(this.state.params || []));
+ }
}
export default Fetch;

8.立即变更数据 #

• useRequest 提供了mutate, 支持立即修改useRequest返回的data参数
• mutate的用法与React.setState一致，支持mutate(newData)和mutate((oldData) => newData)两种写法

8.1 App.js #

src\App.js

import React, { useState, useRef } from 'react';
import { useRequest } from './ahooks';
+let success = true;
+function getName() {
+  return new Promise((resolve, reject) => {
+    setTimeout(() => {
+      if (success) {
+        resolve(`zhufeng`);
+      } else {
+        reject(new Error('获取用户名失败'));
+      }
+      success = !success;
+    }, 1000);
+  });
+}
+let updateSuccess = true;
+function updateName(username) {
+  return new Promise((resolve, reject) => {
+    setTimeout(() => {
+      if (updateSuccess) {
+        resolve(username);
+      } else {
+        reject(new Error(`修改用户名失败`));
+      }
+      updateSuccess = !updateSuccess;
+    }, 1000);
+  });
+}
function App() {
+ const lastRef = useRef();
+ const [value, setValue] = useState("");
+ const { data: name, mutate } = useRequest(getName);
+ const { run, loading } = useRequest(updateName, {
+   manual: true,
+   onSuccess: (result, params) => {
+     setValue("");
+     console.log(`用户名成功变更为 "${params[0]}" !`);
+   },
+   onError: (error, params) => {
+     console.error(error.message);
+     mutate(lastRef.current);
+   }
+ });
  return (
    <>
+     {name && <div>用户名: {name}</div>}
+     <input
+       onChange={(event) => setValue(event.target.value)}
+       value={value}
+       placeholder="请输入用户名"
+     />
+     <button onClick={() => {
+       lastRef.current = name;
+       mutate(value);
+       run(value);
+     }} type="button">
+       {loading ? "更新中......." : '更新'}
+     </button>
    </>
  )
};
export default App;

8.2 useRequestImplement.js #

src\ahooks\useRequest\src\useRequestImplement.js

import useCreation from '../../useCreation';
import useLatest from '../../useLatest';
import useMount from '../../useMount';
import useUpdate from '../../useUpdate';
import Fetch from './Fetch';
import useMemoizedFn from '../../useMemoizedFn';
function useRequestImplement(service, options = {}) {
  const { manual = false, ...rest } = options;
  const fetchOptions = { manual, ...rest };
  const serviceRef = useLatest(service);
  const update = useUpdate();
  const fetchInstance = useCreation(() => {
    return new Fetch(serviceRef, fetchOptions, update);
  }, []);
  useMount(() => {
    if (!manual) {
      const params = fetchInstance.state.params || options.defaultParams || [];
      fetchInstance.run(...params);
    }
  });
  return {
    loading: fetchInstance.state.loading,
    data: fetchInstance.state.data,
    error: fetchInstance.state.error,
    run: useMemoizedFn(fetchInstance.run.bind(fetchInstance)),
    runAsync: useMemoizedFn(fetchInstance.runAsync.bind(fetchInstance)),
    refresh: useMemoizedFn(fetchInstance.refresh.bind(fetchInstance)),
    refreshAsync: useMemoizedFn(fetchInstance.refreshAsync.bind(fetchInstance)),
+   mutate: useMemoizedFn(fetchInstance.mutate.bind(fetchInstance))
  };
}
export default useRequestImplement;

8.3 Fetch.js #

src\ahooks\useRequest\src\Fetch.js

import { isFunction } from '../../utils';
class Fetch {
  constructor(serviceRef, options, subscribe) {
    this.serviceRef = serviceRef;
    this.options = options;
    this.subscribe = subscribe;
    this.state = { loading: false, data: undefined, error: undefined, params: undefined };
  }
  setState = (s = {}) => {
    this.state = { ...this.state, ...s };
    this.subscribe();
  }
  runAsync = async (...params) => {
    this.setState({ loading: true, params });
    this.options.onBefore?.(params);
    try {
      const res = await this.serviceRef.current(...params);
      this.setState({ loading: false, data: res, error: undefined, params });
      this.options.onSuccess?.(res, params);
      this.options.onFinally?.(params, res, undefined);
    } catch (error) {
      this.setState({ loading: false, error, params });
      this.options.onError?.(error, params);
      this.options.onFinally?.(params, undefined, error);
      throw error;
    }
  }
  run = (...params) => {
    this.runAsync(...params).catch(error => {
      if (!this.options.onError) {
        console.error(error);
      }
    });
  }
  refresh() {
    this.run(...(this.state.params || []));
  }

  refreshAsync() {
    return this.runAsync(...(this.state.params || []));
  }
+  mutate(data) {
+    let targetData;
+    if (isFunction(data)) {
+      targetData = data(this.state.data);
+    } else {
+      targetData = data;
+    }
+    this.setState({
+      data: targetData
+    });
+  }
}
export default Fetch;

8.4 utils\index.js #

src\ahooks\utils\index.js

export const isFunction = value => typeof value === 'function';

9.取消请求 #

• useRequest 提供了 cancel 函数，可以取消当前正在进行的请求。同时 useRequest 会在以下时机自动取消当前请求：
  • 组件卸载时，取消正在进行的请求
  • 竞态取消，当上一次请求还没返回时，又发起了下一次请求，则会取消上一次请求

9.1 App.js #

src\App.js

import React, { useState, useRef } from 'react';
import { useRequest } from './ahooks';
let success = true;
function getName() {
  return new Promise((resolve, reject) => {
    setTimeout(() => {
      if (success) {
        resolve(`zhufeng`);
      } else {
        reject(new Error('获取用户名失败'));
      }
      success = !success;
    }, 1000);
  });
}
let updateSuccess = true;
function updateName(username) {
  return new Promise((resolve, reject) => {
    setTimeout(() => {
      if (updateSuccess) {
        resolve(username);
      } else {
        reject(new Error(`修改用户名失败`));
      }
      updateSuccess = !updateSuccess;
+   }, 3000);
  });
}
function App() {
  const lastRef = useRef();
  const [value, setValue] = useState("");
  const { data: name, mutate } = useRequest(getName);
+ const { run, loading, cancel } = useRequest(updateName, {
    manual: true,
    onSuccess: (result, params) => {
      setValue("");
      console.log(`用户名成功变更为 "${params[0]}" !`);
    },
    onError: (error, params) => {
      console.error(error.message);
      mutate(lastRef.current);
    },
+   onCancel: () => {
+     mutate(lastRef.current);
+   }
  });
  return (
    <>
      {name && <div>用户名: {name}</div>}
      <input
        onChange={(event) => setValue(event.target.value)}
        value={value}
        placeholder="请输入用户名"
      />
      <button onClick={() => {
        lastRef.current = name;
        mutate(value);
        run(value);
      }} type="button">
        {loading ? "更新中......." : '更新'}
      </button>
+     <button type="button" onClick={cancel}>
+       取消
+     </button>
    </>
  )
};
export default App;

9.2 useRequestImplement.js #

src\ahooks\useRequest\src\useRequestImplement.js

import useCreation from '../../useCreation';
import useLatest from '../../useLatest';
import useMount from '../../useMount';
import useUpdate from '../../useUpdate';
import Fetch from './Fetch';
import useMemoizedFn from '../../useMemoizedFn';
+import useUnmount from '../../useUnmount';
function useRequestImplement(service, options = {}) {
  const { manual = false, ...rest } = options;
  const fetchOptions = { manual, ...rest };
  const serviceRef = useLatest(service);
  const update = useUpdate();
  const fetchInstance = useCreation(() => {
    return new Fetch(serviceRef, fetchOptions, update);
  }, []);
  useMount(() => {
    if (!manual) {
      const params = fetchInstance.state.params || options.defaultParams || [];
      fetchInstance.run(...params);
    }
  });
+ useUnmount(() => {
+   fetchInstance.cancel();
+ });
  return {
    loading: fetchInstance.state.loading,
    data: fetchInstance.state.data,
    error: fetchInstance.state.error,
    run: useMemoizedFn(fetchInstance.run.bind(fetchInstance)),
    runAsync: useMemoizedFn(fetchInstance.runAsync.bind(fetchInstance)),
    refresh: useMemoizedFn(fetchInstance.refresh.bind(fetchInstance)),
    refreshAsync: useMemoizedFn(fetchInstance.refreshAsync.bind(fetchInstance)),
    mutate: useMemoizedFn(fetchInstance.mutate.bind(fetchInstance)),
+   cancel: useMemoizedFn(fetchInstance.cancel.bind(fetchInstance))
  };
}
export default useRequestImplement;

9.3 Fetch.js #

src\ahooks\useRequest\src\Fetch.js

import { isFunction } from '../../utils';
class Fetch {
+ count = 0;
  constructor(serviceRef, options, subscribe) {
    this.serviceRef = serviceRef;
    this.options = options;
    this.subscribe = subscribe;
    this.state = { loading: false, data: undefined, error: undefined, params: undefined };
  }
  setState = (s = {}) => {
    this.state = { ...this.state, ...s };
    this.subscribe();
  }
  runAsync = async (...params) => {
+   this.count += 1;
+   const currentCount = this.count;
    this.setState({ loading: true, params });
    this.options.onBefore?.(params);
    try {
      const res = await this.serviceRef.current(...params);
+     if (currentCount !== this.count) {
+       return new Promise(() => { });
+     }
      this.setState({ loading: false, data: res, error: undefined, params });
      this.options.onSuccess?.(res, params);
      this.options.onFinally?.(params, res, undefined);
    } catch (error) {
+     if (currentCount !== this.count) {
+       return new Promise(() => { });
+     }
      this.setState({ loading: false, error, params });
      this.options.onError?.(error, params);
      this.options.onFinally?.(params, undefined, error);
      throw error;
    }
  }
  run = (...params) => {
    this.runAsync(...params).catch(error => {
      if (!this.options.onError) {
        console.error(error);
      }
    });
  }
  refresh() {
    this.run(...(this.state.params || []));
  }

  refreshAsync() {
    return this.runAsync(...(this.state.params || []));
  }
  mutate(data) {
    let targetData;

    if (isFunction(data)) {
      targetData = data(this.state.data);
    } else {
      targetData = data;
    }

    this.setState({
      data: targetData
    });
  }
+ cancel() {
+   this.count += 1;
+   this.setState({
+     loading: false
+   });
+   this.options.onCancel?.();
+ }
}
export default Fetch;

9.4 useUnmount\index.js #

src\ahooks\useUnmount\index.js

import { useEffect } from 'react';
import useLatest from '../useLatest';
const useUnmount = fn => {
  const fnRef = useLatest(fn);
  useEffect(() => () => fnRef.current(), []);
};

export default useUnmount;

10.插件系统 #

• useRequest通过插件式组织代码，核心代码极其简单，所有高级功能均是通过插件实现
• 在请求过程中会触发各种各样的事件，可以为这些事件编写钩子函数，而插件就是钩子函数的集合

钩子	说明
onBefore	请求前
onRequest	请求中
onSuccess	请求成功
onError	请求失败
onFinally	请求结束
onCancel	请求取消
onMutate	修改结果数据
onInit	初始化状态

10.1 App.js #

src\App.js

import React, { useState, useRef } from 'react';
import { useRequest } from './ahooks';
let success = true;
function getName() {
  return new Promise((resolve, reject) => {
    setTimeout(() => {
      if (success) {
        resolve(`zhufeng`);
      } else {
        reject(new Error('获取用户名失败'));
      }
      success = !success;
    }, 1000);
  });
}
let updateSuccess = true;
function updateName(username) {
  return new Promise((resolve, reject) => {
    setTimeout(() => {
      if (updateSuccess) {
        resolve(username);
      } else {
        reject(new Error(`修改用户名失败`));
      }
      updateSuccess = !updateSuccess;
    }, 300);
  });
}
function App() {
  const lastRef = useRef();
  const [value, setValue] = useState("");
+ const { data: name, mutate } = useRequest(getName, { name: 'getName' });
  const { run, loading, cancel } = useRequest(updateName, {
    manual: true,
+   name: 'updateName',
    onSuccess: (result, params) => {
      setValue("");
      console.log(`用户名成功变更为 "${params[0]}" !`);
    },
    onError: (error, params) => {
      console.error(error.message);
      mutate(lastRef.current);
    },
    onCancel: () => {
      mutate(lastRef.current);
    }
  });
  return (
    <>
      {name && <div>用户名: {name}</div>}
      <input
        onChange={(event) => setValue(event.target.value)}
        value={value}
        placeholder="请输入用户名"
      />
      <button onClick={() => {
        lastRef.current = name;
        mutate(value);
        run(value);
      }} type="button">
        {loading ? "更新中......." : '更新'}
      </button>
      <button type="button" onClick={cancel}>
        取消
      </button>
    </>
  )
};
export default App;

10.2 useRequest.js #

src\ahooks\useRequest\src\useRequest.js

import useRequestImplement from './useRequestImplement';
+import useLoggerPlugin from './plugins/useLoggerPlugin';
+function useRequest(service, options = {}, plugins) {
+ return useRequestImplement(service, options, [...(plugins || []), useLoggerPlugin]);
}
export default useRequest;

10.3 useRequestImplement.js #

src\ahooks\useRequest\src\useRequestImplement.js

import useCreation from '../../useCreation';
import useLatest from '../../useLatest';
import useMount from '../../useMount';
import useUpdate from '../../useUpdate';
import Fetch from './Fetch';
import useMemoizedFn from '../../useMemoizedFn';
import useUnmount from '../../useUnmount';
+function useRequestImplement(service, options = {}, plugins = []) {
  const { manual = false, ...rest } = options;
  const fetchOptions = { manual, ...rest };
  const serviceRef = useLatest(service);
  const update = useUpdate();
  const fetchInstance = useCreation(() => {
+   const initState = plugins.map(p => p?.onInit?.(fetchOptions)).filter(Boolean);
+   return new Fetch(serviceRef, fetchOptions, update, Object.assign({}, ...initState));
  }, []);
+ //fetchInstance.options = fetchOptions;
+ fetchInstance.pluginImpls = plugins.map(p => p(fetchInstance, fetchOptions));
  useMount(() => {
    if (!manual) {
      const params = fetchInstance.state.params || options.defaultParams || [];
      fetchInstance.run(...params);
    }
  });
  useUnmount(() => {
    fetchInstance.cancel();
  });
  return {
    loading: fetchInstance.state.loading,
    data: fetchInstance.state.data,
    error: fetchInstance.state.error,
    run: useMemoizedFn(fetchInstance.run.bind(fetchInstance)),
    runAsync: useMemoizedFn(fetchInstance.runAsync.bind(fetchInstance)),
    refresh: useMemoizedFn(fetchInstance.refresh.bind(fetchInstance)),
    refreshAsync: useMemoizedFn(fetchInstance.refreshAsync.bind(fetchInstance)),
    mutate: useMemoizedFn(fetchInstance.mutate.bind(fetchInstance)),
    cancel: useMemoizedFn(fetchInstance.cancel.bind(fetchInstance))
  };
}
export default useRequestImplement;

10.4 useLoggerPlugin.js #

src\ahooks\useRequest\src\plugins\useLoggerPlugin.js

const useLoggerPlugin = (fetchInstance, { name }) => {
  return {
    onBefore: () => {
      console.log(name, 'onBefore');
      return { id: name };
    },
    onRequest: () => {
      console.log(name, 'onRequest');
      return { servicePromise: Promise.resolve('onRequest返回值') };
    },
    onSuccess: () => {
      console.log(name, 'onSuccess', fetchInstance.state.name, fetchInstance.state.id);
    },
    onError: () => {
      console.log(name, 'onError');
    },
    onFinally: () => {
      console.log(name, 'onFinally');
    },
    onCancel: () => {
      console.log(name, 'onCancel');
    },
    onMutate: () => {
      console.log(name, 'onMutate');
    },
  };
};
useLoggerPlugin.onInit = ({ name }) => {
  console.log(name, 'onInit')
  return { name };
}
export default useLoggerPlugin;

10.5 Fetch.js #

src\ahooks\useRequest\src\Fetch.js

import { isFunction } from '../../utils';
class Fetch {
  count = 0;
+ constructor(serviceRef, options, subscribe, initState = {}) {
    this.serviceRef = serviceRef;
    this.options = options;
    this.subscribe = subscribe;
+   this.state = { loading: !options.manual, data: undefined, error: undefined, params: undefined, ...initState };
  }
  setState = (s = {}) => {
    this.state = { ...this.state, ...s };
    this.subscribe();
  }
  runAsync = async (...params) => {
    this.count += 1;
    const currentCount = this.count;
+   const { ...state } = this.runPluginHandler('onBefore', params);
+   this.setState({ loading: true, params, ...state });
    this.options.onBefore?.(params);
    try {
+     let { servicePromise } = this.runPluginHandler('onRequest', this.serviceRef.current, params);
+     if (!servicePromise) {
+       servicePromise = this.serviceRef.current(...params);
+     }
+     const res = await servicePromise;
      if (currentCount !== this.count) {
        return new Promise(() => { });
      }
      this.setState({ loading: false, data: res, error: undefined, params });
      this.options.onSuccess?.(res, params);
+     this.runPluginHandler('onSuccess', res, params);
      this.options.onFinally?.(params, res, undefined);
+     if (currentCount === this.count) {
+       this.runPluginHandler('onFinally', params, res, undefined);
+     }
    } catch (error) {
      if (currentCount !== this.count) {
        return new Promise(() => { });
      }
      this.setState({ loading: false, error, params });
      this.options.onError?.(error, params);
+     this.runPluginHandler('onError', error, params);
      this.options.onFinally?.(params, undefined, error);
+     if (currentCount === this.count) {
+       this.runPluginHandler('onFinally', params, undefined, error);
+     }
      throw error;
    }
  }
  run = (...params) => {
    this.runAsync(...params).catch(error => {
      if (!this.options.onError) {
        console.error(error);
      }
    });
  }
  refresh() {
    this.run(...(this.state.params || []));
  }

  refreshAsync() {
    return this.runAsync(...(this.state.params || []));
  }
  mutate(data) {
    let targetData;
    if (isFunction(data)) {
      targetData = data(this.state.data);
    } else {
      targetData = data;
    }
+   this.runPluginHandler('onMutate', targetData);
    this.setState({
      data: targetData
    });
  }
  cancel() {
    this.count += 1;
    this.setState({
      loading: false
    });
    this.options.onCancel?.();
+   this.runPluginHandler('onCancel');
  }
+ runPluginHandler(event, ...rest) {
+   const r = this.pluginImpls.map(i => i[event]?.(...rest)).filter(Boolean);
+   return Object.assign({}, ...r);
+ }
}
export default Fetch;

11.Loading Delay #

• 通过设置 options.loadingDelay，可以延迟 loading 变成 true 的时间，有效防止闪烁

11.1 App.js #

src\App.js

import React, { useState, useRef } from 'react';
import { useRequest } from './ahooks';
let success = true;
function getName() {
  return new Promise((resolve, reject) => {
    setTimeout(() => {
      if (success) {
        resolve(`zhufeng`);
      } else {
        reject(new Error('获取用户名失败'));
      }
      success = !success;
    }, 0);
  });
}
let updateSuccess = true;
function updateName(username) {
  return new Promise((resolve, reject) => {
    setTimeout(() => {
      if (updateSuccess) {
        resolve(username);
      } else {
        reject(new Error(`修改用户名失败`));
      }
      updateSuccess = !updateSuccess;
    }, 3000);
  });
}
function App() {
  const lastRef = useRef();
  const [value, setValue] = useState("");
  const { data: name, mutate } = useRequest(getName, { name: 'getName' });
  const { run, loading, cancel } = useRequest(updateName, {
    manual: true,
    name: 'updateName',
+   loadingDelay: 1000,
    onSuccess: (result, params) => {
      setValue("");
      console.log(`用户名成功变更为 "${params[0]}" !`);
    },
    onError: (error, params) => {
      console.error(error.message);
      mutate(lastRef.current);
    },
    onCancel: () => {
      mutate(lastRef.current);
    }
  });
  return (
    <>
      {name && <div>用户名: {name}</div>}
      <input
        onChange={(event) => setValue(event.target.value)}
        value={value}
        placeholder="请输入用户名"
      />
      <button onClick={() => {
        lastRef.current = name;
        mutate(value);
        run(value);
      }} type="button">
        {loading ? "更新中......." : '更新'}
      </button>
      <button type="button" onClick={cancel}>
        取消
      </button>
    </>
  )
};
export default App;

11.2 useRequest.js #

src\ahooks\useRequest\src\useRequest.js

import useRequestImplement from './useRequestImplement';
+import useLoadingDelayPlugin from './plugins/useLoadingDelayPlugin';
function useRequest(service, options = {}, plugins) {
  return useRequestImplement(service, options, [...(plugins || []),
+   useLoadingDelayPlugin
  ]);
}
export default useRequest;

11.3 useLoadingDelayPlugin.js #

src\ahooks\useRequest\src\plugins\useLoadingDelayPlugin.js

import { useRef } from 'react';
const useLoadingDelayPlugin = (fetchInstance, { loadingDelay }) => {
  const timerRef = useRef();
  if (!loadingDelay) {
    return {};
  }
  const cancelTimeout = () => {
    if (timerRef.current) {
      clearTimeout(timerRef.current);
    }
  };
  return {
    onBefore: () => {
      cancelTimeout();
      timerRef.current = setTimeout(() => {
        fetchInstance.setState({
          loading: true
        });
      }, loadingDelay);
      return {
        loading: false
      };
    },
    onFinally: () => {
      cancelTimeout();
    },
    onCancel: () => {
      cancelTimeout();
    }
  };
};
export default useLoadingDelayPlugin;

12.轮询 #

• 通过设置 options.pollingInterval，进入轮询模式，useRequest 会定时触发service 执行

  12.1 轮询 #

  12.1.1 App.js #

  src\App.js

import React, { useState, useRef } from 'react';
import { useRequest } from './ahooks';
+let counter = 0;
function getName() {
  return new Promise((resolve, reject) => {
    setTimeout(() => {
+     resolve(`zhufeng` + (++counter));
    }, 0);
  });
}
let updateSuccess = true;
function updateName(username) {
  return new Promise((resolve, reject) => {
    setTimeout(() => {
      if (updateSuccess) {
        resolve(username);
      } else {
        reject(new Error(`修改用户名失败`));
      }
      updateSuccess = !updateSuccess;
    }, 3000);
  });
}
function App() {
  const lastRef = useRef();
  const [value, setValue] = useState("");
  const { data: name, mutate } = useRequest(getName, {
    name: 'getName',
+   pollingInterval: 1000
  });
  const { run, loading, cancel } = useRequest(updateName, {
    manual: true,
    name: 'updateName',
    loadingDelay: 1000,
    onSuccess: (result, params) => {
      setValue("");
      console.log(`用户名成功变更为 "${params[0]}" !`);
    },
    onError: (error, params) => {
      console.error(error.message);
      mutate(lastRef.current);
    },
    onCancel: () => {
      mutate(lastRef.current);
    }
  });
  console.log(loading);
  return (
    <>
      {name && <div>用户名: {name}</div>}
      <input
        onChange={(event) => setValue(event.target.value)}
        value={value}
        placeholder="请输入用户名"
      />
      <button onClick={() => {
        lastRef.current = name;
        mutate(value);
        run(value);
      }} type="button">
        {loading ? "更新中......." : '更新'}
      </button>
      <button type="button" onClick={cancel}>
        取消
      </button>
    </>
  )
};
export default App;

12.1.2 useRequest.js #

src\ahooks\useRequest\src\useRequest.js

import useRequestImplement from './useRequestImplement';
import useLoadingDelayPlugin from './plugins/useLoadingDelayPlugin';
+import usePollingPlugin from './plugins/usePollingPlugin';
function useRequest(service, options = {}, plugins) {
  return useRequestImplement(service, options, [...(plugins || []),
    useLoadingDelayPlugin,
+   usePollingPlugin
  ]);
}
export default useRequest;

12.1.3 usePollingPlugin.js #

src\ahooks\useRequest\src\plugins\usePollingPlugin.js

import { useRef } from 'react';
import useUpdateEffect from '../../../useUpdateEffect';
const usePollingPlugin = (fetchInstance, { pollingInterval }) => {
  const timerRef = useRef();
  const stopPolling = () => {
    if (timerRef.current) {
      clearTimeout(timerRef.current);
    }
  };

  useUpdateEffect(() => {
    if (!pollingInterval) {
      stopPolling();
    }
  }, [pollingInterval]);

  if (!pollingInterval) {
    return {};
  }

  return {
    onBefore: () => {
      stopPolling();
    },
    onFinally: () => {
      timerRef.current = setTimeout(() => {
        fetchInstance.refresh();
      }, pollingInterval);
    },
    onCancel: () => {
      stopPolling();
    }
  };
};
export default usePollingPlugin;

12.1.4 useUpdateEffect\index.js #

src\ahooks\useUpdateEffect\index.js

import { useEffect } from 'react';
import { createUpdateEffect } from '../createUpdateEffect';
export default createUpdateEffect(useEffect);

12.1.5 createUpdateEffect\index.js #

src\ahooks\createUpdateEffect\index.js

import { useRef } from 'react';
export const createUpdateEffect = hook => (effect, deps) => {
  const isMounted = useRef(false);
  hook(() => {
    return () => {
      isMounted.current = false;
    };
  }, []);
  hook(() => {
    if (!isMounted.current) {
      isMounted.current = true;
    } else {
      return effect();
    }
  }, deps);
};

12.2 后台轮询 #

12.2.1 src\App.js #

src\App.js

import React, { useState, useRef } from 'react';
import { useRequest } from './ahooks';
let counter = 0;
function getName() {
  return new Promise((resolve, reject) => {
    setTimeout(() => {
      resolve(`zhufeng` + (++counter));
    }, 0);
  });
}
let updateSuccess = true;
function updateName(username) {
  return new Promise((resolve, reject) => {
    setTimeout(() => {
      if (updateSuccess) {
        resolve(username);
      } else {
        reject(new Error(`修改用户名失败`));
      }
      updateSuccess = !updateSuccess;
    }, 3000);
  });
}
function App() {
  const lastRef = useRef();
  const [value, setValue] = useState("");
  const { data: name, mutate } = useRequest(getName, {
    name: 'getName',
    pollingInterval: 1000,
+   pollingWhenHidden: false
  });
  const { run, loading, cancel } = useRequest(updateName, {
    manual: true,
    name: 'updateName',
    loadingDelay: 1000,
    onSuccess: (result, params) => {
      setValue("");
      console.log(`用户名成功变更为 "${params[0]}" !`);
    },
    onError: (error, params) => {
      console.error(error.message);
      mutate(lastRef.current);
    },
    onCancel: () => {
      mutate(lastRef.current);
    }
  });
  return (
    <>
      {name && <div>用户名: {name}</div>}
      <input
        onChange={(event) => setValue(event.target.value)}
        value={value}
        placeholder="请输入用户名"
      />
      <button onClick={() => {
        lastRef.current = name;
        mutate(value);
        run(value);
      }} type="button">
        {loading ? "更新中......." : '更新'}
      </button>
      <button type="button" onClick={cancel}>
        取消
      </button>
    </>
  )
};
export default App;

12.2.2 usePollingPlugin.js #

src\ahooks\useRequest\src\plugins\usePollingPlugin.js

import { useRef } from 'react';
import useUpdateEffect from '../../../useUpdateEffect';
+import isDocumentVisible from '../utils/isDocumentVisible';
+import subscribeReVisible from '../utils/subscribeReVisible';
+const usePollingPlugin = (fetchInstance, { pollingInterval, pollingWhenHidden = true }) => {
  const timerRef = useRef();
+ const unsubscribeRef = useRef();
  const stopPolling = () => {
    if (timerRef.current) {
      clearTimeout(timerRef.current);
    }
+   unsubscribeRef.current?.();
  };

  useUpdateEffect(() => {
    if (!pollingInterval) {
      stopPolling();
    }
  }, [pollingInterval]);

  if (!pollingInterval) {
    return {};
  }

  return {
    onBefore: () => {
      stopPolling();
    },
    onFinally: () => {
+     if (!pollingWhenHidden && !isDocumentVisible()) {
+       unsubscribeRef.current = subscribeReVisible(() => {
+         fetchInstance.refresh();
+       });
+       return;
+     }
      timerRef.current = setTimeout(() => {
        fetchInstance.refresh();
      }, pollingInterval);
    },
    onCancel: () => {
      stopPolling();
    }
  };
};

export default usePollingPlugin;

12.2.3 isDocumentVisible.js #

src\ahooks\useRequest\src\utils\isDocumentVisible.js

export default function isDocumentVisible() {
  return document.visibilityState !== 'hidden';
}

12.2.4 subscribeReVisible.js #

src\ahooks\useRequest\src\utils\subscribeReVisible.js

import isDocumentVisible from './isDocumentVisible';
const listeners = [];

function subscribe(listener) {
  listeners.push(listener);
  return function unsubscribe() {
    const index = listeners.indexOf(listener);
    listeners.splice(index, 1);
  };
}

const revalidate = () => {
  if (!isDocumentVisible()) return;

  for (let i = 0; i < listeners.length; i++) {
    const listener = listeners[i];
    listener();
  }
};

window.addEventListener('visibilitychange', revalidate, false);

export default subscribe;

13.Ready和和依赖更新 #

13.1 自动模式 #

13.1.1 App.js #

src\App.js

import React, { useState } from 'react';
import { useRequest } from './ahooks';
function getName() {
  return new Promise((resolve, reject) => {
    setTimeout(() => {
+     resolve(`zhufeng`);
    }, 1000);
  });
}
function App() {
+ const [ready, setReady] = useState(false);
+ const { data: name, loading } = useRequest(getName, {
+   ready
+ });
+ return (
+   <>
+     <p>
+       Ready: {JSON.stringify(ready)}
+       <button onClick={() => setReady(!ready)}>
+         切换Ready
+       </button>
+     </p>
+     {loading ? '加载中' : name ? <div>用户名: {name}</div> : null}
+   </>
+ );
};
export default App;

13.1.2 useRequest.js #

src\ahooks\useRequest\src\useRequest.js

import useRequestImplement from './useRequestImplement';
import useLoadingDelayPlugin from './plugins/useLoadingDelayPlugin';
import usePollingPlugin from './plugins/usePollingPlugin';
+import useAutoRunPlugin from './plugins/useAutoRunPlugin';
function useRequest(service, options = {}, plugins) {
  return useRequestImplement(service, options, [...(plugins || []),
    useLoadingDelayPlugin,
    usePollingPlugin,
+   useAutoRunPlugin
  ]);
}
export default useRequest;

13.1.3 useAutoRunPlugin.js #

src\ahooks\useRequest\src\plugins\useAutoRunPlugin.js

import { useRef } from 'react';
import useUpdateEffect from '../../../useUpdateEffect';
const useAutoRunPlugin = (fetchInstance, { manual, ready = true, defaultParams = [] }) => {
  const hasAutoRun = useRef(false);
  hasAutoRun.current = false;
  useUpdateEffect(() => {
    if (!manual && ready) {
      hasAutoRun.current = true;
      fetchInstance.run(...defaultParams);
    }
  }, [ready]);
  return {
    onBefore: () => {
      if (!ready) {
        return {
          stopNow: true
        };
      }
    }
  };
};

useAutoRunPlugin.onInit = ({
  ready = true,
  manual
}) => {
  return {
    loading: !manual && ready
  };
};

export default useAutoRunPlugin;

13.1.4 Fetch.js #

src\ahooks\useRequest\src\Fetch.js

import { isFunction } from '../../utils';
class Fetch {
  count = 0;
  constructor(serviceRef, options, subscribe, initState = {}) {
    this.serviceRef = serviceRef;
    this.options = options;
    this.subscribe = subscribe;
    this.state = { loading: !options.manual, data: undefined, error: undefined, params: undefined, ...initState };
  }
  setState = (s = {}) => {
    this.state = { ...this.state, ...s };
    this.subscribe();
  }
  runAsync = async (...params) => {
    this.count += 1;
    const currentCount = this.count;
+   const { stopNow = false, ...state } = this.runPluginHandler('onBefore', params);
+   if (stopNow) {
+     return new Promise(() => { });
+   }
    this.setState({ loading: true, params, ...state });
    this.options.onBefore?.(params);
    try {
      let { servicePromise } = this.runPluginHandler('onRequest', this.serviceRef.current, params);
      if (!servicePromise) {
        servicePromise = this.serviceRef.current(...params);
      }
      const res = await servicePromise;
      if (currentCount !== this.count) {
        return new Promise(() => { });
      }
      this.setState({ loading: false, data: res, error: undefined, params });
      this.options.onSuccess?.(res, params);
      this.runPluginHandler('onSuccess', res, params);
      this.options.onFinally?.(params, res, undefined);
      if (currentCount === this.count) {
        this.runPluginHandler('onFinally', params, res, undefined);
      }
    } catch (error) {
      if (currentCount !== this.count) {
        return new Promise(() => { });
      }
      this.setState({ loading: false, error, params });
      this.options.onError?.(error, params);
      this.runPluginHandler('onError', error, params);
      this.options.onFinally?.(params, undefined, error);
      if (currentCount === this.count) {
        this.runPluginHandler('onFinally', params, undefined, error);
      }
      throw error;
    }
  }
  run = (...params) => {
    this.runAsync(...params).catch(error => {
      if (!this.options.onError) {
        console.error(error);
      }
    });
  }
  refresh() {
    this.run(...(this.state.params || []));
  }

  refreshAsync() {
    return this.runAsync(...(this.state.params || []));
  }
  mutate(data) {
    let targetData;

    if (isFunction(data)) {
      targetData = data(this.state.data);
    } else {
      targetData = data;
    }
    this.runPluginHandler('onMutate', targetData);
    this.setState({
      data: targetData
    });
  }
  cancel() {
    this.count += 1;
    this.setState({
      loading: false
    });
    this.options.onCancel?.();
    this.runPluginHandler('onCancel');
  }
  runPluginHandler(event, ...rest) {
    const r = this.pluginImpls.map(i => i[event]?.(...rest)).filter(Boolean);
    return Object.assign({}, ...r);
  }
}
export default Fetch;

13.2 手动模式 #

13.2.1 App.js #

src\App.js

import React, { useState } from 'react';
import { useRequest } from './ahooks';

function getName() {
  return new Promise((resolve, reject) => {
    setTimeout(() => {
      resolve(`zhufeng`);
    }, 1000);
  });
}
function App() {
  const [ready, setReady] = useState(false);
  const { data: name, loading, run } = useRequest(getName, {
+   manual: true,
    ready
  });
  return (
    <>
      <p>
        Ready: {JSON.stringify(ready)}
        <button onClick={() => setReady(!ready)}>
          切换Ready
        </button>
      </p>
+     <button type="button" onClick={run}>
+       run
+     </button>
      {loading ? '加载中' : name ? <div>用户名: {name}</div> : null}
    </>
  );
};
export default App;

13.3 依赖更新 #

• useRequest 提供了一个 options.refreshDeps 参数，当它的值变化后，会重新触发请求

13.3.1 App.js #

src\App.js

import React, { useState } from 'react';
import { useRequest } from './ahooks';
+let counter = 0;
function getName() {
  return new Promise((resolve, reject) => {
    setTimeout(() => {
+     resolve(`zhufeng` + (++counter));
    }, 1000);
  });
}
function App() {
+ const [userId, setUserId] = useState('1');
+ const { data: name, loading } = useRequest(getName, {
+   refreshDeps: [userId],
+   refreshDepsAction() {
+     console.log('refreshDepsAction');
+   }
+ });
  return (
    <>
+     <input value={userId} onChange={(event) => setUserId(event.target.value)} />
      {loading ? '加载中' : name ? <div>用户名: {name}</div> : null}
    </>
  );
};
export default App;

13.3.2 useAutoRunPlugin.js #

src\ahooks\useRequest\src\plugins\useAutoRunPlugin.js

import { useRef } from 'react';
import useUpdateEffect from '../../../useUpdateEffect';
const useAutoRunPlugin = (fetchInstance, { manual, ready = true, defaultParams = [],
+ refreshDeps = [],
+ refreshDepsAction
}) => {
  const hasAutoRun = useRef(false);
  hasAutoRun.current = false;
  useUpdateEffect(() => {
    if (!manual && ready) {
      hasAutoRun.current = true;
      fetchInstance.run(...defaultParams);
    }
  }, [ready]);
+  useUpdateEffect(() => {
+    if (hasAutoRun.current) {
+      return;
+    }
+    if (!manual) {
+      hasAutoRun.current = true;
+      if (refreshDepsAction) {
+        refreshDepsAction();
+      } else {
+        fetchInstance.refresh();
+      }
+    }
+  }, [...refreshDeps]);
  return {
    onBefore: () => {
      if (!ready) {
        return {
          stopNow: true
        };
      }
    }
  };
};

useAutoRunPlugin.onInit = ({
  ready = true,
  manual
}) => {
  return {
    loading: !manual && ready
  };
};

export default useAutoRunPlugin;

14.屏幕聚焦重新请求 #

• refresh-on-window-focus
• 通过设置 options.refreshOnWindowFocus，在浏览器窗口 refocus 和 revisible 时，会重新发起请求

14.1 App.js #

src\App.js

import React from 'react';
import { useRequest } from './ahooks';
let counter = 0;
function getName() {
  return new Promise((resolve, reject) => {
    setTimeout(() => {
      resolve(`zhufeng` + (++counter));
    }, 1000);
  });
}
function App() {
  const { data: name, loading } = useRequest(getName, {
+   refreshOnWindowFocus: true,
+   focusTimespan: 5000
  });
  return (
    <>
      {loading ? '加载中' : name ? <div>用户名: {name}</div> : null}
    </>
  );
};
export default App;

14.2 useRequest.js #

src\ahooks\useRequest\src\useRequest.js

import useRequestImplement from './useRequestImplement';
import useLoadingDelayPlugin from './plugins/useLoadingDelayPlugin';
import usePollingPlugin from './plugins/usePollingPlugin';
import useAutoRunPlugin from './plugins/useAutoRunPlugin';
+import useRefreshOnWindowFocusPlugin from './plugins/useRefreshOnWindowFocusPlugin';
function useRequest(service, options = {}, plugins) {
  return useRequestImplement(service, options, [...(plugins || []),
    useLoadingDelayPlugin,
    usePollingPlugin,
    useAutoRunPlugin,
+   useRefreshOnWindowFocusPlugin
  ]);
}
export default useRequest;

14.3 useRefreshOnWindowFocusPlugin.js #

src\ahooks\useRequest\src\plugins\useRefreshOnWindowFocusPlugin.js

import { useEffect, useRef } from 'react';
import useUnmount from '../../../useUnmount';
import limit from '../utils/limit';
import subscribeFocus from '../utils/subscribeFocus';

const useRefreshOnWindowFocusPlugin = (fetchInstance, {
  refreshOnWindowFocus,
  focusTimespan = 5000
}) => {
  const unsubscribeRef = useRef();

  const stopSubscribe = () => {
    unsubscribeRef.current?.();
  };

  useEffect(() => {
    if (refreshOnWindowFocus) {
      const limitRefresh = limit(fetchInstance.refresh.bind(fetchInstance), focusTimespan);
      unsubscribeRef.current = subscribeFocus(() => limitRefresh());
    }
    return () => {
      stopSubscribe();
    };
  }, [refreshOnWindowFocus, focusTimespan]);
  useUnmount(() => {
    stopSubscribe();
  });
  return {};
};

export default useRefreshOnWindowFocusPlugin;

14.4 limit.js #

src\ahooks\useRequest\src\utils\limit.js

export default function limit(fn, timespan) {
  let pending = false;
  return (...args) => {
    if (pending) return;
    pending = true;
    fn(...args);
    setTimeout(() => {
      pending = false;
    }, timespan);
  };
}

14.5 subscribeFocus.js #

src\ahooks\useRequest\src\utils\subscribeFocus.js

import isDocumentVisible from './isDocumentVisible';
const listeners = [];

function subscribe(listener) {
  listeners.push(listener);
  return function unsubscribe() {
    const index = listeners.indexOf(listener);
    listeners.splice(index, 1);
  };
}

const revalidate = () => {
  if (!isDocumentVisible()) return;

  for (let i = 0; i < listeners.length; i++) {
    const listener = listeners[i];
    listener();
  }
};

window.addEventListener('visibilitychange', revalidate, false);
window.addEventListener('focus', revalidate, false);

export default subscribe;

15.防抖 #

• debounce
• lodash.debounce
• 通过设置 options.debounceWait，进入防抖模式，此时如果频繁触发 run 或者 runAsync，则会以防抖策略进行请求。

15.1 App.js #

src\App.js

import React from 'react';
import { useRequest } from './ahooks';
let counter = 0;
+function getName(suffix) {
  return new Promise((resolve, reject) => {
    setTimeout(() => {
+     resolve(`zhufeng` + suffix);
    }, 300);
  });
}
function App() {
  const { data: name, loading, run } = useRequest(getName, {
+   manual: true,
+   debounceWait: 1000
  });
  return (
    <>
      <input onChange={(e) => run(e.target.value)} />
      {loading ? '加载中' : name ? <div>用户名: {name}</div> : null}
    </>
  );
};
export default App;

15.2 useRequest.js #

src\ahooks\useRequest\src\useRequest.js

import useRequestImplement from './useRequestImplement';
import useLoadingDelayPlugin from './plugins/useLoadingDelayPlugin';
import usePollingPlugin from './plugins/usePollingPlugin';
import useAutoRunPlugin from './plugins/useAutoRunPlugin';
import useRefreshOnWindowFocusPlugin from './plugins/useRefreshOnWindowFocusPlugin';
+import useDebouncePlugin from './plugins/useDebouncePlugin';
function useRequest(service, options = {}, plugins) {
  return useRequestImplement(service, options, [...(plugins || []),
    useLoadingDelayPlugin,
    usePollingPlugin,
    useAutoRunPlugin,
    useRefreshOnWindowFocusPlugin,
+   useDebouncePlugin
  ]);
}
export default useRequest;

15.3 useDebouncePlugin.js #

src\ahooks\useRequest\src\plugins\useDebouncePlugin.js

import { useEffect, useRef } from 'react';

const useDebouncePlugin = (fetchInstance, { debounceWait }) => {
  const debouncedRef = useRef();
  useEffect(() => {
    if (debounceWait) {
      const originRunAsync = fetchInstance.runAsync.bind(fetchInstance);
      debouncedRef.current = debounce(callback => callback(), debounceWait);
      fetchInstance.runAsync = (...args) => {
        return new Promise((resolve, reject) => {
          debouncedRef.current?.(() => originRunAsync(...args).then(resolve).catch(reject));
        });
      };
    }
  }, [debounceWait]);
  return {};
};
function debounce(fn, wait) {
  let timer;
  return (...args) => {
    if (timer) {
      clearTimeout(timer);
      timer = null;
    }
    timer = setTimeout(() => fn(...args), wait);
  }
}
export default useDebouncePlugin;

16.节流 #

• 通过设置 options.throttleWait，进入节流模式，此时如果频繁触发 run 或者 runAsync，则会以节流策略进行请求

16.1 App.js #

src\App.js

import React from 'react';
import { useRequest } from './ahooks';
function getName(suffix = '') {
  return new Promise((resolve, reject) => {
    setTimeout(() => {
      resolve(`zhufeng` + suffix);
    }, 300);
  });
}
function App() {
  const { data: name, loading, run } = useRequest(getName, {
+   throttleWait: 1000
  });
  return (
    <>
      <input onChange={(e) => run(e.target.value)} />
      {loading ? '加载中' : name ? <div>用户名: {name}</div> : null}
    </>
  );
};
export default App;

16.2 useRequest.js #

src\ahooks\useRequest\src\useRequest.js

import useRequestImplement from './useRequestImplement';
import useLoadingDelayPlugin from './plugins/useLoadingDelayPlugin';
import usePollingPlugin from './plugins/usePollingPlugin';
import useAutoRunPlugin from './plugins/useAutoRunPlugin';
import useRefreshOnWindowFocusPlugin from './plugins/useRefreshOnWindowFocusPlugin';
import useDebouncePlugin from './plugins/useDebouncePlugin';
+import useThrottlePlugin from './plugins/useThrottlePlugin';
function useRequest(service, options = {}, plugins) {
  return useRequestImplement(service, options, [...(plugins || []),
    useLoadingDelayPlugin,
    usePollingPlugin,
    useAutoRunPlugin,
    useRefreshOnWindowFocusPlugin,
    useDebouncePlugin,
+   useThrottlePlugin
  ]);
}
export default useRequest;

16.3 useThrottlePlugin.js #

src\ahooks\useRequest\src\plugins\useThrottlePlugin.js

import { useEffect, useRef } from 'react';
const useThrottlePlugin = (fetchInstance, { throttleWait }) => {
  const throttledRef = useRef();
  useEffect(() => {
    if (throttleWait) {
      const originRunAsync = fetchInstance.runAsync.bind(fetchInstance);
      throttledRef.current = throttle(callback => callback(), throttleWait);
      fetchInstance.runAsync = (...args) => {
        return new Promise((resolve, reject) => {
          throttledRef.current?.(() => originRunAsync(...args).then(resolve).catch(reject));
        });
      };
    }
  }, [throttleWait]);
  return {};
};
function throttle(fn, wait) {
  let lastExecTime = 0;
  const throttledFn = function (...args) {
    const currentTime = Date.now();
    const nextExecTime = lastExecTime + wait;
    if (currentTime >= nextExecTime) {
      fn.apply(this, args);
      lastExecTime = currentTime;
    }
  }
  return throttledFn;
}
export default useThrottlePlugin;

17.错误重试 #

• 通过设置 options.retryCount，指定错误重试次数，则 useRequest 在失败后会进行重试。

17.1 App.js #

src\App.js

import React from 'react';
import { useRequest } from './ahooks';
function getName(suffix = '') {
  return new Promise((resolve, reject) => {
    setTimeout(() => {
      //resolve(`zhufeng` + suffix);
      reject(new Error('获取用户名失败'));
    }, 2000);
  });
}
function App() {
  const { data: name, loading, run } = useRequest(getName, {
+   retryCount: 3
+   retryInterval:1000_
  });
  return (
    <>
      <input onChange={(e) => run(e.target.value)} />
      {loading ? '加载中' : name ? <div>用户名: {name}</div> : null}
    </>
  );
};
export default App;

17.2 useRequest.js #

src\ahooks\useRequest\src\useRequest.js

import useRequestImplement from './useRequestImplement';
import useLoadingDelayPlugin from './plugins/useLoadingDelayPlugin';
import usePollingPlugin from './plugins/usePollingPlugin';
import useAutoRunPlugin from './plugins/useAutoRunPlugin';
import useRefreshOnWindowFocusPlugin from './plugins/useRefreshOnWindowFocusPlugin';
import useDebouncePlugin from './plugins/useDebouncePlugin';
import useThrottlePlugin from './plugins/useThrottlePlugin';
+import useRetryPlugin from './plugins/useRetryPlugin';
function useRequest(service, options = {}, plugins) {
  return useRequestImplement(service, options, [...(plugins || []),
    useLoadingDelayPlugin,
    usePollingPlugin,
    useAutoRunPlugin,
    useRefreshOnWindowFocusPlugin,
    useDebouncePlugin,
    useThrottlePlugin,
+   useRetryPlugin
  ]);
}
export default useRequest;

17.3 useRetryPlugin.js #

src\ahooks\useRequest\src\plugins\useRetryPlugin.js

import { useRef } from 'react';
const useRetryPlugin = (fetchInstance, {
  retryInterval,
  retryCount
}) => {
  const timerRef = useRef();
  const countRef = useRef(0);//重试的次数
  const triggerByRetry = useRef(false);//是否由重试触发

  if (!retryCount) {
    return {};
  }

  return {
    onBefore: () => {
      if (!triggerByRetry.current) {
        countRef.current = 0;
      }

      triggerByRetry.current = false;

      if (timerRef.current) {
        clearTimeout(timerRef.current);
      }
    },
    onSuccess: () => {
      countRef.current = 0;
    },
    onError: () => {
      countRef.current += 1;
      if (retryCount === -1 || countRef.current <= retryCount) {
        const timeout = retryInterval ?? Math.min(1000 * 2 ** countRef.current, 30000);
        timerRef.current = setTimeout(() => {
          triggerByRetry.current = true;
          fetchInstance.refresh();
        }, timeout);
      } else {
        countRef.current = 0;
      }
    },
    onCancel: () => {
      countRef.current = 0;

      if (timerRef.current) {
        clearTimeout(timerRef.current);
      }
    }
  };
};

export default useRetryPlugin;

18.缓存 #

• 如果设置了 options.cacheKey，useRequest 会将当前请求成功的数据缓存起来。下次组件初始化时，如果有缓存数据，我们会优先返回缓存数据，然后在背后发送新请求，也就是 SWR 的能力。
• 你可以通过 options.staleTime设置数据保持新鲜时间，在该时间内，我们认为数据是新鲜的，不会重新发起请求。
• 你也可以通过 options.cacheTime 设置数据缓存时间，超过该时间，我们会清空该条缓存数据。

18.1 SWR #

• swr 实际上是 Cache Control 中新增的一个试验性指令

  Cache-Control: max-age=86400, stale-while-revalidate=172800

  

• 设置了 cacheKey，在组件第二次加载时，会优先返回缓存的内容，然后在背后重新发起请求。你可以通过点击按钮来体验效果

18.1.1 App.js #

src\App.js

import React, { useState } from 'react';
import { useRequest } from './ahooks';
let counter = 0;
function getName() {
  return new Promise((resolve, reject) => {
    setTimeout(() => {
+     resolve({
+       time: new Date().toLocaleTimeString(), data: `zhufeng` + (++counter)
+     });
    }, 2000);
  });
}
+function User() {
+  const { data, loading } = useRequest(getName, {
+    cacheKey: 'cacheKey',
+  });
+  if (!data && loading) {
+    return <p>加载中...</p>;
+  }
+  return (
+    <>
+      <p>后台加载中: {loading ? 'true' : 'false'}</p>
+      <p>最近的请求时间: {data?.time}</p>
+      <p>{data?.data}</p>
+    </>
+  );
+}
function App() {
+ const [visible, setVisible] = useState(true);
+ return (
+   <div>
+     <button type="button" onClick={() => setVisible(!visible)}>
+       {visible ? '隐藏' : '显示'}
+     </button>
+     {visible && <User />}
+   </div>
+ );
};
export default App;

18.1.2 useRequest.js #

src\ahooks\useRequest\src\useRequest.js

import useRequestImplement from './useRequestImplement';
import useLoadingDelayPlugin from './plugins/useLoadingDelayPlugin';
import usePollingPlugin from './plugins/usePollingPlugin';
import useAutoRunPlugin from './plugins/useAutoRunPlugin';
import useRefreshOnWindowFocusPlugin from './plugins/useRefreshOnWindowFocusPlugin';
import useDebouncePlugin from './plugins/useDebouncePlugin';
import useThrottlePlugin from './plugins/useThrottlePlugin';
import useRetryPlugin from './plugins/useRetryPlugin';
+import useCachePlugin from './plugins/useCachePlugin';
function useRequest(service, options = {}, plugins) {
  return useRequestImplement(service, options, [...(plugins || []),
    useLoadingDelayPlugin,
    usePollingPlugin,
    useAutoRunPlugin,
    useRefreshOnWindowFocusPlugin,
    useDebouncePlugin,
    useThrottlePlugin,
    useRetryPlugin,
+   useCachePlugin
  ]);
}
export default useRequest;

18.1.3 useCachePlugin.js #

src\ahooks\useRequest\src\plugins\useCachePlugin.js

import * as cache from '../utils/cache';
const useCachePlugin = (fetchInstance, {
  cacheKey
}) => {
  const _setCache = (key, cachedData) => {
    cache.setCache(key, cachedData);
  };

  const _getCache = (key) => {
    return cache.getCache(key);
  };

  if (!cacheKey) {
    return {};
  }

  return {
    onBefore: params => {
      const cacheData = _getCache(cacheKey, params);
      if (!cacheData || !Object.hasOwnProperty.call(cacheData, 'data')) {
        return {};
      }
      return {
        data: cacheData?.data
      };
    },
    onSuccess: (data, params) => {
      if (cacheKey) {
        _setCache(cacheKey, {
          data,
          params,
          time: new Date().getTime()
        });
      }
    }
  };
};

export default useCachePlugin;

18.1.4 cache.js #

src\ahooks\useRequest\src\utils\cache.js

const cache = new Map();

const setCache = (key, cachedData) => {
  cache.set(key, {
    ...cachedData
  });
};

const getCache = key => {
  return cache.get(key);
};

export { getCache, setCache };

18.2 数据保持新鲜 #

• 通过设置 staleTime，我们可以指定数据新鲜时间，在这个时间内，不会重新发起请求。下面的示例设置了 5s 的新鲜时间

18.2.1 App.js #

src\App.js

import React, { useState } from 'react';
import { useRequest } from './ahooks';
let counter = 0;
function getName() {
  return new Promise((resolve, reject) => {
    setTimeout(() => {
      resolve({
        time: new Date().toLocaleTimeString(), data: `zhufeng` + (++counter)
      });
    }, 2000);
  });
}
function User() {
  const { data, loading } = useRequest(getName, {
    cacheKey: 'cacheKey',
+   staleTime: 5000
  });
  if (!data && loading) {
    return <p>加载中...</p>;
  }
  return (
    <>
      <p>后台加载中: {loading ? 'true' : 'false'}</p>
      <p>最近的请求时间: {data?.time}</p>
      <p>{data?.data}</p>
    </>
  );
}
function App() {
  const [visible, setVisible] = useState(true);
  return (
    <div>
      <button type="button" onClick={() => setVisible(!visible)}>
        {visible ? '隐藏' : '显示'}
      </button>
      {visible && <User />}
    </div>
  );
};
export default App;

18.2.2 useCachePlugin.js #

src\ahooks\useRequest\src\plugins\useCachePlugin.js

import * as cache from '../utils/cache';
const useCachePlugin = (fetchInstance, {
  cacheKey,
+ staleTime = 0,
}) => {
  const _setCache = (key, cachedData) => {
    cache.setCache(key, cachedData);
  };

  const _getCache = (key) => {
    return cache.getCache(key);
  };

  if (!cacheKey) {
    return {};
  }

  return {
    onBefore: params => {
      const cacheData = _getCache(cacheKey, params);
      if (!cacheData || !Object.hasOwnProperty.call(cacheData, 'data')) {
        return {};
      }
+     if (staleTime === -1 || new Date().getTime() - cacheData.time <= staleTime) {
+       return {
+         loading: false,
+         data: cacheData?.data,
+         returnNow: true
+       };
+     } else {
        return {
          data: cacheData?.data
        };
+     }
    },
    onSuccess: (data) => {
      if (cacheKey) {
        _setCache(cacheKey, {
          data,
          time: new Date().getTime()
        });
      }
    }
  };
};

export default useCachePlugin;

18.2.3 Fetch.js #

src\ahooks\useRequest\src\Fetch.js

import { isFunction } from '../../utils';
class Fetch {
  count = 0;
  constructor(serviceRef, options, subscribe, initState = {}) {
    this.serviceRef = serviceRef;
    this.options = options;
    this.subscribe = subscribe;
    this.state = { loading: !options.manual, data: undefined, error: undefined, params: undefined, ...initState };
  }
  setState = (s = {}) => {
    this.state = { ...this.state, ...s };
    this.subscribe();
  }
  runAsync = async (...params) => {
    this.count += 1;
    const currentCount = this.count;
+   const { stopNow = false, returnNow = false, ...state } = this.runPluginHandler('onBefore', params);
    if (stopNow) {
      return new Promise(() => { });
    }
    this.setState({ loading: true, params, ...state });
+   if (returnNow) {
+     return Promise.resolve(state.data);
+   }
    this.options.onBefore?.(params);
    try {
      let { servicePromise } = this.runPluginHandler('onRequest', this.serviceRef.current, params);
      if (!servicePromise) {
        servicePromise = this.serviceRef.current(...params);
      }
      const res = await servicePromise;
      if (currentCount !== this.count) {
        return new Promise(() => { });
      }
      this.setState({ loading: false, data: res, error: undefined, params });
      this.options.onSuccess?.(res, params);
      this.runPluginHandler('onSuccess', res, params);
      this.options.onFinally?.(params, res, undefined);
      if (currentCount === this.count) {
        this.runPluginHandler('onFinally', params, res, undefined);
      }
    } catch (error) {
      if (currentCount !== this.count) {
        return new Promise(() => { });
      }
      this.setState({ loading: false, error, params });
      this.options.onError?.(error, params);
      this.runPluginHandler('onError', error, params);
      this.options.onFinally?.(params, undefined, error);
      if (currentCount === this.count) {
        this.runPluginHandler('onFinally', params, undefined, error);
      }
      throw error;
    }
  }
  run = (...params) => {
    this.runAsync(...params).catch(error => {
      if (!this.options.onError) {
        console.error(error);
      }
    });
  }
  refresh() {
    this.run(...(this.state.params || []));
  }

  refreshAsync() {
    return this.runAsync(...(this.state.params || []));
  }
  mutate(data) {
    let targetData;

    if (isFunction(data)) {
      targetData = data(this.state.data);
    } else {
      targetData = data;
    }
    this.runPluginHandler('onMutate', targetData);
    this.setState({
      data: targetData
    });
  }
  cancel() {
    this.count += 1;
    this.setState({
      loading: false
    });
    this.options.onCancel?.();
    this.runPluginHandler('onCancel');
  }
  runPluginHandler(event, ...rest) {
    const r = this.pluginImpls.map(i => i[event]?.(...rest)).filter(Boolean);
    return Object.assign({}, ...r);
  }
}
export default Fetch;

18.3 参数缓存 #

• 缓存的数据包括 data 和 params，通过 params 缓存机制，我们可以记忆上一次请求的条件，并在下次初始化。

18.3.1 App.js #

src\App.js

import React, { useState } from 'react';
import { useRequest } from './ahooks';
let counter = 0;
+function getName(keyword = '') {
  return new Promise((resolve, reject) => {
    setTimeout(() => {
      resolve({
+       time: new Date().toLocaleTimeString(), data: keyword + (++counter)
      });
    }, 2000);
  });
}
function User() {
+ const { data, loading, params, run } = useRequest(getName, {
-   manual: true,
    cacheKey: 'cacheKey',
+   staleTime: 0
  });
+ const [keyword, setKeyword] = useState(params[0] || "");
  if (!data && loading) {
    return <p>加载中...</p>;
  }
  return (
    <>
+     <div>
+       <input
+         value={keyword}
+         onChange={(e) => setKeyword(e.target.value)}
+       />
+       <button
+         onClick={() => {
+           run(keyword);
+         }}
+       >
+         获取用户名
+       </button>
+     </div>
      <p>后台加载中: {loading ? 'true' : 'false'}</p>
      <p>最近的请求时间: {data?.time}</p>
      <p>Keyword: {keyword}</p>
      <p>{data?.data}</p>
    </>
  );
}
function App() {
  const [visible, setVisible] = useState(true);
  return (
    <div>
      <button type="button" onClick={() => setVisible(!visible)}>
        {visible ? '隐藏' : '显示'}
      </button>
      {visible && <User />}
    </div>
  );
};
export default App;

18.3.2 useRequestImplement.js #

src\ahooks\useRequest\src\useRequestImplement.js

import useCreation from '../../useCreation';
import useLatest from '../../useLatest';
import useMount from '../../useMount';
import useUpdate from '../../useUpdate';
import Fetch from './Fetch';
import useMemoizedFn from '../../useMemoizedFn';
import useUnmount from '../../useUnmount';
function useRequestImplement(service, options = {}, plugins = []) {
  const { manual = false, ...rest } = options;
  const fetchOptions = { manual, ...rest };
  const serviceRef = useLatest(service);
  const update = useUpdate();
  const fetchInstance = useCreation(() => {
    const initState = plugins.map(p => p?.onInit?.(fetchOptions)).filter(Boolean);
    return new Fetch(serviceRef, fetchOptions, update, Object.assign({}, ...initState));
  }, []);
  //fetchInstance.options = fetchOptions;
  fetchInstance.pluginImpls = plugins.map(p => p(fetchInstance, fetchOptions));
  useMount(() => {
    if (!manual) {
      const params = fetchInstance.state.params || options.defaultParams || [];
      fetchInstance.run(...params);
    }
  });
  useUnmount(() => {
    fetchInstance.cancel();
  });
  return {
    loading: fetchInstance.state.loading,
    data: fetchInstance.state.data,
    error: fetchInstance.state.error,
+   params: fetchInstance.state.params || [],
    run: useMemoizedFn(fetchInstance.run.bind(fetchInstance)),
    runAsync: useMemoizedFn(fetchInstance.runAsync.bind(fetchInstance)),
    refresh: useMemoizedFn(fetchInstance.refresh.bind(fetchInstance)),
    refreshAsync: useMemoizedFn(fetchInstance.refreshAsync.bind(fetchInstance)),
    mutate: useMemoizedFn(fetchInstance.mutate.bind(fetchInstance)),
    cancel: useMemoizedFn(fetchInstance.cancel.bind(fetchInstance))
  };
}

export default useRequestImplement;

18.3.3 useCachePlugin.js #

src\ahooks\useRequest\src\plugins\useCachePlugin.js

import * as cache from '../utils/cache';
+import useCreation from '../../../useCreation';
const useCachePlugin = (fetchInstance, {
  cacheKey,
  staleTime = 0,
}) => {
  const _setCache = (key, cachedData) => {
    cache.setCache(key, cachedData);
  };

  const _getCache = (key) => {
    return cache.getCache(key);
  };
+ useCreation(() => {
+   if (!cacheKey) {
+     return;
+   }
+   const cacheData = _getCache(cacheKey);
+   if (cacheData && Object.hasOwnProperty.call(cacheData, 'data')) {
+     fetchInstance.state.data = cacheData.data;
+     fetchInstance.state.params = cacheData.params;
+     if (staleTime === -1 || new Date().getTime() - cacheData.time <= staleTime) {
+       fetchInstance.state.loading = false;
+     }
+   }
+ })
  if (!cacheKey) {
    return {};
  }

  return {
    onBefore: params => {
      const cacheData = _getCache(cacheKey, params);
      if (!cacheData || !Object.hasOwnProperty.call(cacheData, 'data')) {
        return {};
      }
      if (staleTime === -1 || new Date().getTime() - cacheData.time <= staleTime) {
        return {
          loading: false,
          data: cacheData?.data,
          returnNow: true
        };
      } else {
        return {
          data: cacheData?.data
        };
      }
    },
    onSuccess: (data, params) => {
      if (cacheKey) {
        _setCache(cacheKey, {
          data,
          params,
          time: new Date().getTime()
        });
      }
    }
  };
};

export default useCachePlugin;

18.4 删除缓存 #

• ahooks 提供了一个 clearCache 方法，可以清除指定 cacheKey 的缓存数据。

18.4.1 App.js #

src\App.js

import React, { useState } from 'react';
+import { useRequest, clearCache } from './ahooks';
let counter = 0;
function getName(keyword = '') {
  return new Promise((resolve, reject) => {
    setTimeout(() => {
      resolve({
        time: new Date().toLocaleTimeString(), data: keyword + (++counter)
      });
    }, 2000);
  });
}
function User() {
  const { data, loading, params, run } = useRequest(getName, {
    cacheKey: 'cacheKey',
+   staleTime: 5000
  });
  const [keyword, setKeyword] = useState(params[0] || "");
  if (!data && loading) {
    return <p>加载中...</p>;
  }
  return (
    <>
      <div>
        <input
          value={keyword}
          onChange={(e) => setKeyword(e.target.value)}
        />
        <button
          onClick={() => {
            run(keyword);
          }}
        >
          获取用户名
        </button>
      </div>
+     <button onClick={() => clearCache('cacheKey')}>
+       清除缓存
+     </button>
      <p>后台加载中: {loading ? 'true' : 'false'}</p>
      <p>最近的请求时间: {data?.time}</p>
      <p>Keyword: {keyword}</p>
      <p>{data?.data}</p>
    </>
  );
}
function App() {
  const [visible, setVisible] = useState(true);
  return (
    <div>
      <button type="button" onClick={() => setVisible(!visible)}>
        {visible ? '隐藏' : '显示'}
      </button>
      {visible && <User />}
    </div>
  );
};
export default App;

18.4.2 ahooks\index.js #

src\ahooks\index.js

+import useRequest, { clearCache } from './useRequest';
export {
+  useRequest, clearCache
}

18.4.3 useRequest\index.js #

src\ahooks\useRequest\index.js

import useRequest from './src/useRequest';
+import { clearCache } from './src/utils/cache';
+export default useRequest;
+export { clearCache };

18.4.4 cache.js #

src\ahooks\useRequest\src\utils\cache.js

const cache = new Map();

const setCache = (key, cachedData) => {
  cache.set(key, {
    ...cachedData
  });
};

const getCache = key => {
  return cache.get(key);
};

+const clearCache = key => {
+  if (key) {
+    const cacheKeys = Array.isArray(key) ? key : [key];
+    cacheKeys.forEach(cacheKey => cache.delete(cacheKey));
+  } else {
+    cache.clear();
+  }
+};
export { getCache, setCache, clearCache };

18.5 自定义缓存 #

• 通过配置 setCache 和 getCache，可以自定义数据缓存，比如可以将数据存储到 localStorage、IndexDB 等

18.5.1 App.js #

src\App.js

import React, { useState } from 'react';
import { useRequest, clearCache } from './ahooks';
let counter = 0;
function getName(keyword = '') {
  return new Promise((resolve, reject) => {
    setTimeout(() => {
      resolve({
        time: new Date().toLocaleTimeString(), data: keyword + (++counter)
      });
    }, 2000);
  });
}
function User() {
  const { data, loading, params, run } = useRequest(getName, {
    cacheKey: 'cacheKey',
    staleTime: 5000,
+   setCache: (data) => localStorage.setItem('cacheKey', JSON.stringify(data)),
+   getCache: () => JSON.parse(localStorage.getItem('cacheKey') || '{}'),
  });
  const [keyword, setKeyword] = useState(params[0] || "");
  if (!data && loading) {
    return <p>加载中...</p>;
  }
  return (
    <>
      <div>
        <input
          value={keyword}
          onChange={(e) => setKeyword(e.target.value)}
        />
        <button
          onClick={() => {
            run(keyword);
          }}
        >
          获取用户名
        </button>
      </div>
      <button onClick={() => clearCache('cacheKey')}>
        清除缓存
      </button>
      <p>后台加载中: {loading ? 'true' : 'false'}</p>
      <p>最近的请求时间: {data?.time}</p>
      <p>Keyword: {keyword}</p>
      <p>{data?.data}</p>
    </>
  );
}
function App() {
  const [visible, setVisible] = useState(true);
  return (
    <div>
      <button type="button" onClick={() => setVisible(!visible)}>
        {visible ? '隐藏' : '显示'}
      </button>
      {visible && <User />}
    </div>
  );
};
export default App;

18.5.2 useCachePlugin.js #

src\ahooks\useRequest\src\plugins\useCachePlugin.js

import * as cache from '../utils/cache';
import useCreation from '../../../useCreation';
const useCachePlugin = (fetchInstance, {
  cacheKey,
  staleTime = 0,
+ cacheTime = 5 * 60 * 1000,
+ setCache: customSetCache,
+ getCache: customGetCache
}) => {
  const _setCache = (key, cachedData) => {
+    if (customSetCache) {
+      customSetCache(cachedData);
+    } else {
       cache.setCache(key, cacheTime, cachedData);
+    }
  };

  const _getCache = (key, params) => {
+   if (customGetCache) {
+     return customGetCache(params);
+   }
    return cache.getCache(key);
  };
  useCreation(() => {
    if (!cacheKey) {
      return;
    }
    const cacheData = _getCache(cacheKey);
    if (cacheData && Object.hasOwnProperty.call(cacheData, 'data')) {
      fetchInstance.state.data = cacheData.data;
      fetchInstance.state.params = cacheData.params;
      if (staleTime === -1 || new Date().getTime() - cacheData.time <= staleTime) {
        fetchInstance.state.loading = false;
      }
    }
  })
  if (!cacheKey) {
    return {};
  }

  return {
    onBefore: params => {
      const cacheData = _getCache(cacheKey, params);
      if (!cacheData || !Object.hasOwnProperty.call(cacheData, 'data')) {
        return {};
      }
      if (staleTime === -1 || new Date().getTime() - cacheData.time <= staleTime) {
        return {
          loading: false,
          data: cacheData?.data,
          returnNow: true
        };
      } else {
        return {
          data: cacheData?.data
        };
      }
    },
    onSuccess: (data, params) => {
      if (cacheKey) {
        _setCache(cacheKey, {
          data,
          params,
          time: new Date().getTime()
        });
      }
    }
  };
};
export default useCachePlugin;

18.6 数据共享 #

• 同一个 cacheKey 的内容，在全局是共享的，这会带来以下几个特性
  • 请求 Promise 共享，相同的 cacheKey 同时只会有一个在发起请求，后发起的会共用同一个请求 Promise
  • 数据同步，任何时候，当我们改变其中某个 cacheKey 的内容时，其它相同 cacheKey 的内容均会同步

18.6.1 App.js #

src\App.js

import React from 'react';
import { useRequest } from './ahooks';
let counter = 0;
function getName() {
  return new Promise((resolve, reject) => {
    setTimeout(() => {
      resolve({
+       time: new Date().toLocaleTimeString(), data: 'zhufeng' + (++counter)
      });
    }, 2000);
  });
}
function User() {
+ const { data, loading, refresh } = useRequest(getName, {
+   cacheKey: 'cacheKey',
+ });
+ return (
+   <>
+     <p>后台加载中: {loading ? 'true' : 'false'}</p>
+     <button onClick={refresh} type="button">
+       更新
+     </button>
+     <p>最近的请求时间: {data?.time}</p>
+     <p>{data?.data}</p>
+   </>
+ );
}
function App() {
  return (
    <div>
+     <User />
+     <hr />
+     <User />
    </div>
  );
};
export default App;

18.6.2 useCachePlugin.js #

src\ahooks\useRequest\src\plugins\useCachePlugin.js

import { useRef } from 'react';
import * as cache from '../utils/cache';
import useCreation from '../../../useCreation';
+import * as cachePromise from '../utils/cachePromise';
+import * as cacheSubscribe from '../utils/cacheSubscribe';
const useCachePlugin = (fetchInstance, {
  cacheKey,
  staleTime = 0,
  cacheTime = 5 * 60 * 1000,
  setCache: customSetCache,
  getCache: customGetCache
}) => {
+ const unSubscribeRef = useRef();
+ const currentPromiseRef = useRef();
  const _setCache = (key, cachedData) => {
    if (customSetCache) {
      customSetCache(cachedData);
    } else {
      cache.setCache(key, cacheTime, cachedData);
    }
+   cacheSubscribe.trigger(key, cachedData.data);
  };

  const _getCache = (key, params) => {
    if (customGetCache) {
      return customGetCache(params);
    }
    return cache.getCache(key);
  };
  useCreation(() => {
    if (!cacheKey) {
      return;
    }
    const cacheData = _getCache(cacheKey);
    if (cacheData && Object.hasOwnProperty.call(cacheData, 'data')) {
      fetchInstance.state.data = cacheData.data;
      fetchInstance.state.params = cacheData.params;
      if (staleTime === -1 || new Date().getTime() - cacheData.time <= staleTime) {
        fetchInstance.state.loading = false;
      }
    }
  })
  if (!cacheKey) {
    return {};
  }

  return {
    onBefore: params => {
      const cacheData = _getCache(cacheKey, params);
      if (!cacheData || !Object.hasOwnProperty.call(cacheData, 'data')) {
        return {};
      }
      if (staleTime === -1 || new Date().getTime() - cacheData.time <= staleTime) {
        return {
          loading: false,
          data: cacheData?.data,
          returnNow: true
        };
      } else {
        return {
          data: cacheData?.data
        };
      }
    },
+   onRequest: (service, args) => {
+     let servicePromise = cachePromise.getCachePromise(cacheKey);
+     if (servicePromise && servicePromise !== currentPromiseRef.current) {
+       return {
+         servicePromise
+       };
+     }
+     servicePromise = service(...args);
+     currentPromiseRef.current = servicePromise;
+     cachePromise.setCachePromise(cacheKey, servicePromise);
+     return {
+       servicePromise
+     };
+   },
    onSuccess: (data, params) => {
      if (cacheKey) {
        _setCache(cacheKey, {
          data,
          params,
          time: new Date().getTime()
        });
+       unSubscribeRef.current = cacheSubscribe.subscribe(cacheKey, d => {
+         fetchInstance.setState({
+           data: d
+         });
+       });
+     }
    }
  };
};
export default useCachePlugin;

18.6.3 cachePromise.js #

src\ahooks\useRequest\src\utils\cachePromise.js

const cachePromise = new Map();

const getCachePromise = cacheKey => {
  return cachePromise.get(cacheKey);
};

const setCachePromise = (cacheKey, promise) => {
  cachePromise.set(cacheKey, promise);
  promise.then(res => {
    cachePromise.delete(cacheKey);
    return res;
  }).catch(() => {
    cachePromise.delete(cacheKey);
  });
};

export { getCachePromise, setCachePromise };

18.6.4 cacheSubscribe.js #

src\ahooks\useRequest\src\utils\cacheSubscribe.js

const listeners = {};

const trigger = (key, data) => {
  if (listeners[key]) {
    listeners[key].forEach(item => item(data));
  }
};

const subscribe = (key, listener) => {
  if (!listeners[key]) {
    listeners[key] = [];
  }

  listeners[key].push(listener);
  return function unsubscribe() {
    const index = listeners[key].indexOf(listener);
    listeners[key].splice(index, 1);
  };
};
export { trigger, subscribe };