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

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。

其他回答

Julen的解决方案有点难以阅读,这里有更清晰和准确的反应代码,供那些根据标题而不是问题的微小细节绊倒他的人使用。

Tl;dr版本:当你要更新到观察者发送调用一个调度方法,反过来实际上会通知观察者(或执行ajax等)

使用示例组件jsfiddle完成jsfiddle

var InputField = React.createClass({

    getDefaultProps: function () {
        return {
            initialValue: '',
            onChange: null
        };
    },

    getInitialState: function () {
        return {
            value: this.props.initialValue
        };
    },

    render: function () {
        var state = this.state;
        return (
            <input type="text"
                   value={state.value}
                   onChange={this.onVolatileChange} />
        );
    },

    onVolatileChange: function (event) {
        this.setState({ 
            value: event.target.value 
        });

        this.scheduleChange();
    },

    scheduleChange: _.debounce(function () {
        this.onChange();
    }, 250),

    onChange: function () {
        var props = this.props;
        if (props.onChange != null) {
            props.onChange.call(this, this.state.value)
        }
    },

});

与其在debounce()中包装handleOnChange,不如在debounce()中包装回调函数中的ajax调用,从而不破坏事件对象。就像这样:

handleOnChange: function (event) {
   debounce(
     $.ajax({})
  , 250);
}

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>
  );
}

对于debounce,你需要在event.persist()中保留原始的合成事件。下面是用React 16+测试的工作示例。

import React, { Component } from 'react';
import debounce from 'lodash/debounce'

class ItemType extends Component {

  evntHandler = debounce((e) => {
    console.log(e)
  }, 500);

  render() {
    return (
      <div className="form-field-wrap"
      onClick={e => {
        e.persist()
        this.evntHandler(e)
      }}>
        ...
      </div>
    );
  }
}
export default ItemType;

使用功能组件,您可以做到这一点-

const Search = ({ getBooks, query }) => {

  const handleOnSubmit = (e) => {
    e.preventDefault();
  }
  const debouncedGetBooks = debounce(query => {
    getBooks(query);
  }, 700);

  const onInputChange = e => {
    debouncedGetBooks(e.target.value)
  }

  return (
    <div className="search-books">
      <Form className="search-books--form" onSubmit={handleOnSubmit}>
        <Form.Group controlId="formBasicEmail">
          <Form.Control type="text" onChange={onInputChange} placeholder="Harry Potter" />
          <Form.Text className="text-muted">
            Search the world's most comprehensive index of full-text books.
          </Form.Text>
        </Form.Group>
        <Button variant="primary" type="submit">
          Search
        </Button>
      </Form>
    </div>
  )
}

引用- - - - - - ——https://gist.github.com/elijahmanor/08fc6c8468c994c844213e4a4344a709 ——https://blog.revathskumar.com/2016/02/reactjs-using-debounce-in-react-components.html

我们需要将setter传递给debpublished方法:

以下是StackBlitz的一个例子:

import React from "react";
import debounce from "lodash/debounce";

export default function App() {
  const [state, setState] = React.useState({
    debouncedLog: ""
  });

  const debouncedLog = React.useCallback(
    debounce((setState, log) => {
      setState(prevState => ({
        ...prevState,
        debouncedLog: log
      }));
    }, 500),
    []
  );

  const onChange = React.useCallback(({ target: { value: log } }) => {
    debouncedLog(setState, log); // passing the setState along...
  }, []);
  return (
    <div>
      <input onChange={onChange} style={{ outline: "1px blue solid" }} />

      <pre>Debounced Value: {state.debouncedLog}</pre>
    </div>
  );
}

祝你好运…