如何在React.js中执行debounce ?

我想撤消handleOnChange。

我尝试debounce(这。handleOnChange, 200)但它不起作用。

function debounce(fn, delay) {
  var timer = null;
  return function() {
    var context = this,
      args = arguments;
    clearTimeout(timer);
    timer = setTimeout(function() {
      fn.apply(context, args);
    }, delay);
  };
}

var SearchBox = React.createClass({
  render: function() {
    return <input type="search" name="p" onChange={this.handleOnChange} />;
  },

  handleOnChange: function(event) {
    // make ajax call
  }
});

当前回答

如果你正在使用redux,你可以通过中间件以一种非常优雅的方式做到这一点。你可以这样定义Debounce中间件:

var timeout;
export default store => next => action => {
  const { meta = {} } = action;
  if(meta.debounce){
    clearTimeout(timeout);
    timeout = setTimeout(() => {
      next(action)
    }, meta.debounce)
  }else{
    next(action)
  }
}

然后你可以添加debounging到动作创建者,比如:

export default debouncedAction = (payload) => ({
  type : 'DEBOUNCED_ACTION',
  payload : payload,
  meta : {debounce : 300}
}

实际上已经有中间件你可以脱离npm来为你做这件事。

其他回答

I was searching for a solution to the same problem and came across this thread as well as some others but they had the same problem: if you are trying to do a handleOnChange function and you need the value from an event target, you will get cannot read property value of null or some such error. In my case, I also needed to preserve the context of this inside the debounced function since I'm executing a fluxible action. Here's my solution, it works well for my use case so I'm leaving it here in case anyone comes across this thread:

// at top of file:
var myAction = require('../actions/someAction');

// inside React.createClass({...});

handleOnChange: function (event) {
    var value = event.target.value;
    var doAction = _.curry(this.context.executeAction, 2);

    // only one parameter gets passed into the curried function,
    // so the function passed as the first parameter to _.curry()
    // will not be executed until the second parameter is passed
    // which happens in the next function that is wrapped in _.debounce()
    debouncedOnChange(doAction(myAction), value);
},

debouncedOnChange: _.debounce(function(action, value) {
    action(value);
}, 300)

你也可以使用自己编写的mixin,就像这样:

var DebounceMixin = {
  debounce: function(func, time, immediate) {
    var timeout = this.debouncedTimeout;
    if (!timeout) {
      if (immediate) func();
      this.debouncedTimeout = setTimeout(function() {
        if (!immediate) func();
        this.debouncedTimeout = void 0;
      }.bind(this), time);
    }
  }
};

然后像这样在你的组件中使用它:

var MyComponent = React.createClass({
  mixins: [DebounceMixin],
  handleClick: function(e) {
    this.debounce(function() {
      this.setState({
        buttonClicked: true
      });
    }.bind(this), 500, true);
  },
  render: function() {
    return (
      <button onClick={this.handleClick}></button>
    );
  }
});

我在这个问题下找不到任何答案,提到我正在使用的方法,所以只想在这里提供一个替代解决方案,我认为这是最适合我的用例。

如果您正在使用流行的react钩子工具包库react-use,那么有一个名为useDebounce()的实用工具钩子,它以一种相当优雅的方式实现了谴责逻辑。

const [query, setQuery] = useState('');

useDebounce(
  () => {
    emitYourOnDebouncedSearchEvent(query);
  },
  2000,
  [query]
);

return <input onChange={({ currentTarget }) => setQuery(currentTarget.value)} />

有关详细信息,请直接检查库的github页面。

https://github.com/streamich/react-use/blob/master/docs/useDebounce.md

扩展useState钩子

import { useState } from "react";
import _ from "underscore"
export const useDebouncedState = (initialState, durationInMs = 500) => {
    const [internalState, setInternalState] = useState(initialState);
    const debouncedFunction = _.debounce(setInternalState, durationInMs);
    return [internalState, debouncedFunction];
};
export default useDebouncedState;

使用钩

import useDebouncedState from "../hooks/useDebouncedState"
//...
const [usernameFilter, setUsernameFilter] = useDebouncedState("")
//...
<input id="username" type="text" onChange={e => setUsernameFilter(e.target.value)}></input>

https://trippingoncode.com/react-debounce-hook/

我的解决方案是基于钩子(用Typescript编写)。

我有2个主要钩子useDebouncedValue和useDebouncedCallback

First - useDebouncedValue

假设我们有一个搜索框,但是我们想在用户停止输入0.5秒后向服务器请求搜索结果

function SearchInput() {
  const [realTimeValue, setRealTimeValue] = useState('');

  const debouncedValue = useDebouncedValue(realTimeValue, 500); // this value will pick real time value, but will change it's result only when it's seattled for 500ms

  useEffect(() => {
    // this effect will be called on seattled values
    api.fetchSearchResults(debouncedValue);
  }, [debouncedValue])

  return <input onChange={event => setRealTimeValue(event.target.value)} />
}

实现

import { useState, useEffect } from "react";

export function useDebouncedValue<T>(input: T, time = 500) {
  const [debouncedValue, setDebouncedValue] = useState(input);

  // every time input value has changed - set interval before it's actually commited
  useEffect(() => {
    const timeout = setTimeout(() => {
      setDebouncedValue(input);
    }, time);

    return () => {
      clearTimeout(timeout);
    };
  }, [input, time]);

  return debouncedValue;
}

第二个useDebouncedCallback

它只是在你的组件范围内创建一个“debpublished”函数。

假设我们有一个带有按钮的组件,在你停止点击它后,它将显示警报500毫秒。

function AlertButton() {
  function showAlert() {
    alert('Clicking has seattled');
  }

  const debouncedShowAlert = useDebouncedCallback(showAlert, 500);

  return <button onClick={debouncedShowAlert}>Click</button>
}

实现(注意我使用lodash/debounce作为辅助)

import debounce from 'lodash/debounce';
import { useMemo } from 'react';

export function useDebouncedCallback<T extends (...args: any) => any>(callback: T, wait?: number) {
  const debouncedCallback = useMemo(() => debounce(callback, wait), [callback, wait]);

  return debouncedCallback;
}