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

如果我们有兴趣在react.js中使用epic.js,我们可以在epic.js库中使用debounceTime rxjs/操作符。因此,我们可以在epic.js的帮助下,在react.js中使用可观察对象,而不是使用回调。

其他回答

你试过吗?

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) {
    debounce(\\ Your handleChange code , 200);
  }
});

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>
    );
  }
});

至于2021年6月,您可以简单地实现xnimorz解决方案:https://github.com/xnimorz/use-debounce

import { useState, useEffect, useRef } from "react";
// Usage
function App() {
  // State and setters for ...
  // Search term
  const [searchTerm, setSearchTerm] = useState("");
  // API search results
  const [results, setResults] = useState([]);
  // Searching status (whether there is pending API request)
  const [isSearching, setIsSearching] = useState(false);
  // Debounce search term so that it only gives us latest value ...
  // ... if searchTerm has not been updated within last 500ms.
  // The goal is to only have the API call fire when user stops typing ...
  // ... so that we aren't hitting our API rapidly.
  const debouncedSearchTerm = useDebounce(searchTerm, 500);
  // Effect for API call
  useEffect(
    () => {
      if (debouncedSearchTerm) {
        setIsSearching(true);
        searchCharacters(debouncedSearchTerm).then((results) => {
          setIsSearching(false);
          setResults(results);
        });
      } else {
        setResults([]);
        setIsSearching(false);
      }
    },
    [debouncedSearchTerm] // Only call effect if debounced search term changes
  );
  return (
    <div>
      <input
        placeholder="Search Marvel Comics"
        onChange={(e) => setSearchTerm(e.target.value)}
      />
      {isSearching && <div>Searching ...</div>}
      {results.map((result) => (
        <div key={result.id}>
          <h4>{result.title}</h4>
          <img
            src={`${result.thumbnail.path}/portrait_incredible.${result.thumbnail.extension}`}
          />
        </div>
      ))}
    </div>
  );
}
// API search function
function searchCharacters(search) {
  const apiKey = "f9dfb1e8d466d36c27850bedd2047687";
  return fetch(
    `https://gateway.marvel.com/v1/public/comics?apikey=${apiKey}&titleStartsWith=${search}`,
    {
      method: "GET",
    }
  )
    .then((r) => r.json())
    .then((r) => r.data.results)
    .catch((error) => {
      console.error(error);
      return [];
    });
}
// Hook
function useDebounce(value, delay) {
  // State and setters for debounced value
  const [debouncedValue, setDebouncedValue] = useState(value);
  useEffect(
    () => {
      // Update debounced value after delay
      const handler = setTimeout(() => {
        setDebouncedValue(value);
      }, delay);
      // Cancel the timeout if value changes (also on delay change or unmount)
      // This is how we prevent debounced value from updating if value is changed ...
      // .. within the delay period. Timeout gets cleared and restarted.
      return () => {
        clearTimeout(handler);
      };
    },
    [value, delay] // Only re-call effect if value or delay changes
  );
  return debouncedValue;
}

你可以在ReactJS钩子中使用一个use-debounce包。

从包的README:

import { useDebounce } from 'use-debounce';

export default function Input() {
  const [text, setText] = useState('Hello');
  const [value] = useDebounce(text, 1000);

  return (
    <div>
      <input
        defaultValue={'Hello'}
        onChange={(e) => {
          setText(e.target.value);
        }}
      />
      <p>Actual value: {text}</p>
      <p>Debounce value: {value}</p>
    </div>
  );
}

从上面的示例中可以看到,它设置为每秒钟更新一次变量值(1000毫秒)。

2019:使用“useCallback”反应钩子

在尝试了许多不同的方法之后,我发现使用useCallback是解决在onChange事件中使用debounce的多次调用问题的最简单和最有效的方法。

根据Hooks API文档,

useCallback返回回调的一个记忆版本,只有当其中一个依赖项发生变化时才会发生变化。

将空数组作为依赖项传递可以确保只调用一次回调。下面是一个简单的实现:

import React, { useCallback } from "react";
import { debounce } from "lodash";

const handler = useCallback(debounce(someFunction, 2000), []);
    
const onChange = (event) => {
    // perform any event related action here
    
    handler();
 };