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
}
});
你必须使用useCallback,正如在这篇博客中提到的:
https://www.freecodecamp.org/news/debounce-and-throttle-in-react-with-hooks/
import React, { useCallback } from 'react';
import debounce from 'debounce'; // or another package
function App() {
...
const debouncedSave = useCallback(
debounce(x => foo(x), 1000),
[], // will be created only once initially
);
...
}
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/
不受控制的组件
你可以使用event.persist()方法。
下面是一个使用下划线_.debounce()的例子:
var SearchBox = React.createClass({
componentWillMount: function () {
this.delayedCallback = _.debounce(function (event) {
// `event.target` is accessible now
}, 1000);
},
onChange: function (event) {
event.persist();
this.delayedCallback(event);
},
render: function () {
return (
<input type="search" onChange={this.onChange} />
);
}
});
编辑:请看这个JSFiddle
控制组件
更新:上面的例子显示了一个不受控制的组件。我一直在使用受控元素,这里是上面的另一个例子,但没有使用event.persist()“欺骗”。
JSFiddle也是可用的。不带下划线的示例
var SearchBox = React.createClass({
getInitialState: function () {
return {
query: this.props.query
};
},
componentWillMount: function () {
this.handleSearchDebounced = _.debounce(function () {
this.props.handleSearch.apply(this, [this.state.query]);
}, 500);
},
onChange: function (event) {
this.setState({query: event.target.value});
this.handleSearchDebounced();
},
render: function () {
return (
<input type="search"
value={this.state.query}
onChange={this.onChange} />
);
}
});
var Search = React.createClass({
getInitialState: function () {
return {
result: this.props.query
};
},
handleSearch: function (query) {
this.setState({result: query});
},
render: function () {
return (
<div id="search">
<SearchBox query={this.state.result}
handleSearch={this.handleSearch} />
<p>You searched for: <strong>{this.state.result}</strong></p>
</div>
);
}
});
React.render(<Search query="Initial query" />, document.body);
编辑:更新示例和JSFiddles到React 0.12
编辑:更新的例子,以解决Sebastien Lorber提出的问题
编辑:更新的jsfiddle不使用下划线和使用纯javascript debounce。
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。