前端RxJs响应式编程之操作符实践

常用操作符

本地使用环境为rollup rxjs，具体的rollup配置，请参考另一篇文章，这里不再赘述。

import { of,Observable, interval,Subject ,from,bindCallback} from 'rxjs';
import { version } from './package.json';
import { ajax } from 'rxjs/ajax';
import { map, catchError } from 'rxjs/operators';

const someFunction = (a, b, c) => {
    console.log("a"); // 5
    console.log("b"); // 'some string'
    console.log("c"); // {someProperty: 'someValue'}
  };
   
  const boundSomeFunction = bindCallback(someFunction);
  boundSomeFunction().subscribe(values => {
    console.log(values) // [5, 'some string', {someProperty: 'someValue'}]
  });

from

 //逐行输出 1，2，3
import { from} from 'rxjs';
const arr = [1,2,3];
const result$ = from(arr);
result$.subscribe(res => console.log(res));

range

 //逐行输出 1-10
 import { range } from 'rxjs';

const numbers = range(1, 10);
numbers.subscribe(x => console.log(x));

timer

 //1 ....
 import { timer } from 'rxjs';

const numbers = timer(3000,1000); //延迟3s，定时1s
numbers.subscribe(x => console.log(x 1));

interval

 // 1....
 import { interval } from 'rxjs';

const numbers = interval(1000);
numbers.subscribe(x => console.log(x 1));

of

 // 输出数组  [1,2,3]
 import { of } from "rxjs";

const arr = [1,2,3]
const result$ = of(arr);
result$.subscribe(res => console.log(res));

// 逐行1，2,3
const result$ = of(1,2,3);
result$.subscribe(res => console.log(res));

条件判断

 import { defer, fromEvent, interval,of } from 'rxjs';
 
const clicksOrInterval = defer(() => { //es6 支持
    return Math.random() > 0
    ? of('click')
    : interval(1000);
});
clicksOrInterval.subscribe(x => console.log(x));

import { defer, fromEvent, interval,of, iif } from 'rxjs';
let isFisrt;
const clicksOrInterval = iif(
    () => isFisrt,
    of('first'),
    of('second')
);
isFisrt = true;
clicksOrInterval.subscribe(x => console.log(x));

isFisrt = false;
clicksOrInterval.subscribe(x => console.log(x));

延迟

import { fromEvent ,of} from 'rxjs';
import { delay } from 'rxjs/operators';

const res = of(1,2,3);
const delayedClicks = res.pipe(delay(1000)); // each click emitted after 1 second
delayedClicks.subscribe(x => console.log(x));

防抖

import { fromEvent } from 'rxjs';
import { throttle } from 'rxjs/operators';

const clicks = fromEvent(document, 'click');
const result = clicks.pipe(throttle(ev => interval(1000)));
result.subscribe(x => console.log(x));

map

import { of} from 'rxjs';
import { delay,map} from 'rxjs/operators'; //注意map引入

const res = of(1,2,3);
const delayedClicks = res.pipe(map(item => item * 2)); // each click emitted after 1 second
delayedClicks.subscribe(x => console.log(x));

filter

import { of} from 'rxjs';
import { delay,filter} from 'rxjs/operators';

const res = of(1,2,3);
const delayedClicks = res.pipe(filter(item => item % 2 === 0)); // each click emitted after 1 second
delayedClicks.subscribe(x => console.log(x));

本文作者：前端首席体验师(CheongHu)

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