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
}
});
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)。
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);
}
});
下面是我想出的一个用debouncer包装另一个类的例子。这使得自己很好地成为一个装饰器/高阶函数:
export class DebouncedThingy extends React.Component {
static ToDebounce = ['someProp', 'someProp2'];
constructor(props) {
super(props);
this.state = {};
}
// On prop maybe changed
componentWillReceiveProps = (nextProps) => {
this.debouncedSetState();
};
// Before initial render
componentWillMount = () => {
// Set state then debounce it from here on out (consider using _.throttle)
this.debouncedSetState();
this.debouncedSetState = _.debounce(this.debouncedSetState, 300);
};
debouncedSetState = () => {
this.setState(_.pick(this.props, DebouncedThingy.ToDebounce));
};
render() {
const restOfProps = _.omit(this.props, DebouncedThingy.ToDebounce);
return <Thingy {...restOfProps} {...this.state} />
}
}
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…