rxjs 常用的管道操作符

操作符文档

api 列表

do -> tap

catch -> catchError

switch -> switchAll

finally -> finalize

map switchMap mergeMap

scan 和 reduce

// res: 12, 15

from([2, 3]).pipe(

  scan((acc, item) => acc += item, 10))

  .subscribe(v => console.log(v))

// res: 15

from([2, 3]).pipe(

  reduce((acc, item) => acc += item, 10))

  .subscribe(v => console.log(v))

filter 和 partition

from([2, 3, 4]).pipe(

    filter(item => item <= 3))

    .subscribe(v => console.log(v))

pairwise()

of(1, 2, 3)

  .pipe(

    pairwise()).subscribe(v => console.log(v))

[1,2]

[2,3]

min，max，count

from([1,2]).pipe(max()).subscribe(l) // 2

from([1,2]).pipe(min()).subscribe(l) // 1

from([1,2]).pipe(count()).subscribe(l) // 2

distinct(lambda) distinctUntilChanged([(Prev, current)=>{}]) 和 distinctUntilKeyChanged(key)

from([1, 2, 2, 3, 2])

  .pipe(distinct())

  .subscribe(l); // 1,2,3

elementAt

from([1, 2])

  .pipe(elementAt(0, "default value"))

  .subscribe(l);

ignoreElements()

skip(count: Number)，skipLast(count: number)，skipWhile(lambda)

take(count: number)， takeLast(count: number)，takeUntil(notifier: Observable)，takeWhile(lambda)

throttle(lambda: Observable)和 throttleTime(number)

audit(lambda: Observable)和 auditTime(number)

    interval(500)

      .pipe(auditTime(1000))

      .subscribe(l); // 1s后发出 2, 1被忽略

debounce(lambda: Observable) 和 debounceTime(number)

sample(Observable) 和 sampleTime(number)

find 和 findIndex

toPromise

  click = async e => {

    let res = await ajax('http://localhost:1995/a').pipe(map(res => res.response)).toPromise();

    l(res)

  }

buffer bufferCount bufferTime bufferToggle bufferWhen

const send$= fromEvent(document, 'click');

const interval = interval(1000);

const buffered = interval.pipe(buffer(send$));

buffered.subscribe(l);

defaultIfEmpty

const { of, from, empty } = require("rxjs");

const { mergeMap, defaultIfEmpty } = require("rxjs/operators");

from([1, 2, 2, 3, 2])

  .pipe(

    mergeMap(el => (el > 10 ? of(el) : empty())),

    defaultIfEmpty("not data"),

  )

  .subscribe(l); // not data

delay delayWhen

endWith

from([1, 2])

  .pipe(endWith("源观察完成后，附加一个发射，然后完成。"))

  .subscribe(l); // 1, 2, "源观察完成后，附加一个发射，然后完成。"

不常用的

pluck(properties: ...string); 取一个对象的属性类似 obj.xxx.xxx

toArray(); 把流发出的值塞在Array后，返回Array