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
}
});
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…
使用React Hooks和响应式编程(RxJS)的React ajax debounce和cancel示例解决方案:
import React, { useEffect, useState } from "react";
import { ajax } from "rxjs/ajax";
import { debounceTime, delay, takeUntil } from "rxjs/operators";
import { Subject } from "rxjs/internal/Subject";
const App = () => {
const [items, setItems] = useState([]);
const [loading, setLoading] = useState(true);
const [filterChangedSubject] = useState(() => {
// Arrow function is used to init Singleton Subject. (in a scope of a current component)
return new Subject<string>();
});
useEffect(() => {
// Effect that will be initialized once on a react component init.
const subscription = filterChangedSubject
.pipe(debounceTime(200))
.subscribe((filter) => {
if (!filter) {
setLoading(false);
setItems([]);
return;
}
ajax(`https://swapi.dev/api/people?search=${filter}`)
.pipe(
// current running ajax is canceled on filter change.
takeUntil(filterChangedSubject)
)
.subscribe(
(results) => {
// Set items will cause render:
setItems(results.response.results);
},
() => {
setLoading(false);
},
() => {
setLoading(false);
}
);
});
return () => {
// On Component destroy. notify takeUntil to unsubscribe from current running ajax request
filterChangedSubject.next("");
// unsubscribe filter change listener
subscription.unsubscribe();
};
}, []);
const onFilterChange = (e) => {
// Notify subject about the filter change
filterChangedSubject.next(e.target.value);
};
return (
<div>
Cards
{loading && <div>Loading...</div>}
<input onChange={onFilterChange}></input>
{items && items.map((item, index) => <div key={index}>{item.name}</div>)}
</div>
);
};
export default App;
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}
/>
);
}
2022 -使用useEffect钩子
此时最好的选择是使用useEffect钩子。useEffect允许您设置一个函数,该函数可以修改状态以响应某些异步事件。debounging是异步的,因此useEffect可以很好地用于此目的。
如果从钩子返回一个函数,返回的函数将在钩子再次被调用之前被调用。这让您可以取消之前的超时,有效地解除函数。
例子
这里我们有两个状态,value和tempValue。设置tempValue将触发useEffect钩子,该钩子将启动一个1000ms超时,该超时将调用一个函数将tempValue复制为value。
钩子返回一个取消定时器设置的函数。当钩子再次被调用时(即按下另一个键),超时被取消并重置。
const DebounceDemo = () => {
const [value, setValue] = useState();
const [tempValue, setTempValue] = useState();
// This hook will set a 1000 ms timer to copy tempValue into value
// If the hook is called again, the timer will be cancelled
// This creates a debounce
useEffect(
() => {
// Wait 1000ms before copying the value of tempValue into value;
const timeout = setTimeout(() => {
setValue(tempValue);
}, 1000);
// If the hook is called again, cancel the previous timeout
// This creates a debounce instead of a delay
return () => clearTimeout(timeout);
},
// Run the hook every time the user makes a keystroke
[tempValue]
)
// Here we create an input to set tempValue.
// value will be updated 1000 ms after the hook is last called,
// i.e after the last user keystroke.
return (
<>
<input
onChange={
({ target }) => setTempValue(target.value)
}
/>
<p>{ value }</p>
</>
)
}
在与文本输入斗争了一段时间后,我自己没有找到一个完美的解决方案,我在npm上发现了这个:react-debounce-input。
这里有一个简单的例子:
import React from 'react';
import ReactDOM from 'react-dom';
import {DebounceInput} from 'react-debounce-input';
class App extends React.Component {
state = {
value: ''
};
render() {
return (
<div>
<DebounceInput
minLength={2}
debounceTimeout={300}
onChange={event => this.setState({value: event.target.value})} />
<p>Value: {this.state.value}</p>
</div>
);
}
}
const appRoot = document.createElement('div');
document.body.appendChild(appRoot);
ReactDOM.render(<App />, appRoot);
DebounceInput组件接受您可以分配给普通输入元素的所有道具。在codeen上试试吧
我希望这也能帮助其他人,节省他们的时间。