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
}
});
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();
};
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/
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;
}
