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
}
});
今天遇到了这个问题。使用setTimeout和clearTimeout解决。
我将给出一个你可以适应的例子:
import React, { Component } from 'react'
const DEBOUNCE_TIME = 500
class PlacesAutocomplete extends Component {
debounceTimer = null;
onChangeHandler = (event) => {
// Clear the last registered timer for the function
clearTimeout(this.debounceTimer);
// Set a new timer
this.debounceTimer = setTimeout(
// Bind the callback function to pass the current input value as arg
this.getSuggestions.bind(null, event.target.value),
DEBOUNCE_TIME
)
}
// The function that is being debounced
getSuggestions = (searchTerm) => {
console.log(searchTerm)
}
render() {
return (
<input type="text" onChange={this.onChangeHandler} />
)
}
}
export default PlacesAutocomplete
你也可以在它自己的函数组件中重构它:
import React from 'react'
function DebouncedInput({ debounceTime, callback}) {
let debounceTimer = null
return (
<input type="text" onChange={(event) => {
clearTimeout(debounceTimer);
debounceTimer = setTimeout(
callback.bind(null, event.target.value),
debounceTime
)
}} />
)
}
export default DebouncedInput
像这样使用它:
import React, { Component } from 'react'
import DebouncedInput from '../DebouncedInput';
class PlacesAutocomplete extends Component {
debounceTimer = null;
getSuggestions = (searchTerm) => {
console.log(searchTerm)
}
render() {
return (
<DebouncedInput debounceTime={500} callback={this.getSuggestions} />
)
}
}
export default PlacesAutocomplete
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
避免使用event.persist()——你想让React回收合成事件。我认为无论你使用类还是钩子,最干净的方法是将回调函数分成两部分:
没有deboundation的回调
只使用您需要的事件片段调用已撤销的函数(这样合成的事件就可以循环使用)
类
handleMouseOver = throttle(target => {
console.log(target);
}, 1000);
onMouseOver = e => {
this.handleMouseOver(e.target);
};
<div onMouseOver={this.onMouseOver} />
功能
const handleMouseOver = useRef(throttle(target => {
console.log(target);
}, 1000));
function onMouseOver(e) {
handleMouseOver.current(e.target);
}
<div onMouseOver={this.onMouseOver} />
注意,如果你的handleMouseOver函数从组件中使用状态,你应该使用usemo而不是useRef,并将它们作为依赖项传递,否则你将使用过时的数据(当然不适用于类)。
FYI
这是另一个PoC实现:
没有任何库(例如lodash)用于debound
使用React Hooks API
我希望它能帮助你:)
import React, { useState, useEffect, ChangeEvent } from 'react';
export default function DebouncedSearchBox({
inputType,
handleSearch,
placeholder,
debounceInterval,
}: {
inputType?: string;
handleSearch: (q: string) => void;
placeholder: string;
debounceInterval: number;
}) {
const [query, setQuery] = useState<string>('');
const [timer, setTimer] = useState<NodeJS.Timer | undefined>();
useEffect(() => {
if (timer) {
clearTimeout(timer);
}
setTimer(setTimeout(() => {
handleSearch(query);
}, debounceInterval));
}, [query]);
const handleOnChange = (e: ChangeEvent<HTMLInputElement>): void => {
setQuery(e.target.value);
};
return (
<input
type={inputType || 'text'}
className="form-control"
placeholder={placeholder}
value={query}
onChange={handleOnChange}
/>
);
}