throttle

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

以某个时间间隔为阈值，在 durationSelector 完成前将抑制新值的发出\

示例

示例 1: 节流2秒，时间由第2个 observable 决定

( StackBlitz | jsBin | jsFiddle )

// RxJS v6+
import { interval } from 'rxjs';
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

( StackBlitz | jsBin | jsFiddle )

// RxJS v6+
import { interval } from 'rxjs';
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