throttle

签名: throttle(durationSelector: function(value): Observable | Promise): Observable

仅当由提供的函数所确定的持续时间已经过去时才发出值。

示例

示例 1: 节流2秒，时间由第2个 observable 决定

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jsFiddle )

import { interval } from 'rxjs/observable/interval';
import { throttle } from 'rxjs/operators';
// 每1秒发出值
const source = interval(1000);
// 节流2秒后才发出最新值
const example = source.pipe(throttle(val => interval(2000)));
// 输出: 0...3...6...9
const subscribe = example.subscribe(val => console.log(val));

示例 2: 使用 promise 进行节流

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jsFiddle )

import { interval } from 'rxjs/observable/interval';
import { throttle, map } from 'rxjs/operators';
// 每1秒发出值
const source = interval(1000);
// 基于 source 自增地增加解析的时间
const promise = val =>
  new Promise(resolve =>
    setTimeout(() => resolve(`Resolved: ${val}`), val * 100)
  );
// 当 promise 解析时发出 source 的项
const example = source
  .pipe(
    throttle(promise),
    map(val => `Throttled off Promise: ${val}`);
  );
const subscribe = example.subscribe(val => console.log(val));

其他资源

• throttle - 官方文档
• 过滤操作符: throttle 和 throttleTime - André Staltz

源码: https://github.com/ReactiveX/rxjs/blob/master/src/internal/operators/throttle.ts