安装PubSubJS工具库
npm install pubsub-js --save
A组件订阅消息
import React, { useState } from "react";
import PubSub from "pubsub-js";
export default function ComponentA() {
const [num, selectNum] = useState(0);
//消息订阅
PubSub.subscribe("pubAdd", (_, stateObj) => {
selectNum(num + stateObj * 1);
});
return (
<div>
<h2>子组件A:{num}</h2>
<hr />
</div>
);
}
B组件发布消息
import React, { useRef } from "react";
import PubSub from "pubsub-js";
export default function ComponentB() {
const inputRef = useRef();
function handleAdd() {
// 消息发布
PubSub.publish("pubAdd", inputRef.current.value);
}
return (
<div>
<h2>子组件B</h2>
<select ref={inputRef} name="" id="">
<option value="1">1</option>
<option value="2">2</option>
<option value="3">3</option>
</select>
<button onClick={handleAdd}>添加</button>
<hr />
</div>
);
}
卸载组件前取消订阅
使用useEffect的return函数在组件销毁前取消订阅
import React, { useState, useEffect } from "react";
import PubSub from "pubsub-js";
export default function ComponentA() {
const [num, selectNum] = useState(0);
const handleAdd = (subName, data) => {
console.log(subName, data);
selectNum(num + data * 1);
};
//消息订阅
const addSub = PubSub.subscribe("pubAdd", handleAdd);
useEffect(() => {
return () => {
// 卸载组件前取消订阅
PubSub.unsubscribe(addSub);
};
}, []);
return (
<div>
<h2>子组件A:{num}</h2>
<hr />
</div>
);
}