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

/**
 * Returns a function with the same signature of input `callback` (but without an output) that if called, smartly
 * executes the `callback` in a debounced way.<br>
 * There is no `delay` (to execute the `callback`) in the self-delayed tries (try = calling debounced callback). It
 * will defer **only** subsequent tries (that are earlier than a minimum timeout (`delay` ms) after the latest
 * execution). It also **cancels stale tries** (that have been obsoleted because of creation of newer tries during the
 * same timeout).<br>
 * The timeout won't be expanded! So **the subsequent execution won't be deferred more than `delay`**, at all.
 * @param {Function} callback
 * @param {number} [delay=167] Defaults to `167` that is equal to "10 frames at 60 Hz" (`10 * (1000 / 60) ~= 167 ms`)
 * @return {Function}
 */
export function smartDebounce (callback, delay = 167) {
  let minNextExecTime = 0
  let timeoutId

  function debounced (...args) {
    const now = new Date().getTime()
    if (now > minNextExecTime) { // execute immediately
      minNextExecTime = now + delay // there would be at least `delay` ms between ...
      callback.apply(this, args) // ... two consecutive executions
      return
    }
    // schedule the execution:
    clearTimeout(timeoutId) // unset possible previous scheduling
    timeoutId = setTimeout( // set new scheduling
      () => {
        minNextExecTime = now + delay // there would be at least `delay` ms between ...
        callback.apply(this, args) // ... two consecutive executions
      },
      minNextExecTime - now, // 0 <= timeout <= `delay` ... (`minNextExecTime` <= `now` + `delay`)
    )
  }

  debounced.clear = clearTimeout.bind(null, timeoutId)

  return debounced
}
/**
 * Like React's `useCallback`, but will {@link smartDebounce smartly debounce} future executions.
 * @param {Function} callback
 * @param {[]} deps
 * @param {number} [delay=167] - Defaults to `167` that is equal to "10 frames at 60 Hz" (`10 * (1000 / 60) ~= 167 ms`)
 */
export const useDebounced = (callback, deps, delay = 167) =>
  useMemo(() => smartDebounce(callback, delay), [...deps, delay])

一个漂亮干净的解决方案,不需要任何外部依赖:

与React挂钩反弹

它使用了一个自定义加上useEffect React钩子和setTimeout / clearTimeout方法。

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>
    );
  }
});

您可以使用引用变量来存储计时器,然后将其清除。下面是一个不使用任何第三方包在react中实现deboundation的例子

import { useState, useRef } from "react";
import "./styles.css";

export default function App() {
  // Variables for debouncing
  const [text, setText] = useState("");
  const timer = useRef();

  // Variables for throtteling
  const [throttle, setThrottle] = useState(false)


  const handleDebouncing = ({ target }) => {
    clearTimeout(timer.current)

    timer.current = setTimeout(() => {
      callApi();
    }, 300);

    setText(target.value);
  };

  const handleThrottleing = () => {
    callApi()

    setThrottle(true)

    setTimeout(() => {
      setThrottle(false)
    }, 2000)
  }

  const callApi = () => {
    console.log("Calling Api");
  };

  return (
    <div className="App">
      <input type="text" onChange={handleDebouncing} />

      <button onClick={handleThrottleing} disabled={throttle} >Click me to see throtteling</button>
    </div>
  );
}

如果你只需要从事件对象中获取DOM输入元素,解决方案就简单多了——只需要使用ref。注意,这需要下划线:

class Item extends React.Component {
    constructor(props) {
        super(props);
        this.saveTitle = _.throttle(this.saveTitle.bind(this), 1000);
    }
    saveTitle(){
        let val = this.inputTitle.value;
        // make the ajax call
    }
    render() {
        return <input 
                    ref={ el => this.inputTitle = el } 
                    type="text" 
                    defaultValue={this.props.title} 
                    onChange={this.saveTitle} />
    }
}