publish
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2023-12-01
publish
函数签名: publish() : ConnectableObservable
共享源 observable 并通过调用 connect 方法使其变成热的。
示例
示例 1: 在订阅之后调用 observable 的 connect 方法
( StackBlitz | jsBin | jsFiddle )
// RxJS v6+
import { interval } from 'rxjs';
import { publish, tap } from 'rxjs/operators';
// 每1秒发出值
const source = interval(1000);
const example = source.pipe(
// 副作用只会执行1次
tap(_ => console.log('Do Something!')),
// 不会做任何事直到 connect() 被调用
publish()
);
/*
source 不会发出任何值直到 connect() 被调用
输出: (5秒后)
"Do Something!"
"Subscriber One: 0"
"Subscriber Two: 0"
"Do Something!"
"Subscriber One: 1"
"Subscriber Two: 1"
*/
const subscribe = example.subscribe(val =>
console.log(`Subscriber One: ${val}`)
);
const subscribeTwo = example.subscribe(val =>
console.log(`Subscriber Two: ${val}`)
);
// 5秒后调用 connect,这会使得 source 开始发出值
setTimeout(() => {
example.connect();
}, 5000);
其他资源
- publish :newspaper: - 官方文档
源码: https://github.com/ReactiveX/rxjs/blob/master/src/internal/operators/publish.ts