const x = of(66).pipe(delay(1000));
const c = interval(1000);
// merge(c, x).subscribe(x => console.log(x)); // 0,66,1,2,3,4...
// concat(c, x).subscribe(x => console.log(x)); // 0,1,2,3,4,5,6...
比較merge和concat
zip:
要至少一個obsevable完成,纔會停止訂閱:
const c = interval(1000);
const d = interval(1000).pipe(take(2));
// zip(c, d).subscribe(x => console.log('zip: ', x)); // [0,0] [1,1]
// zip(of(5), d).subscribe(x => console.log('zip: ', x)); // [5,0]
ngOnInit() {
const x = of(1).pipe(delay(1000));
const y = of(3).pipe(delay(3000));
const z = of(4).pipe(delay(4000));
const k = timer(1000, 1000).pipe(mapTo('233'));
// zip(x, y, z, k).subscribe(x => console.log('zip: ', x));
// combineLatest(x, y, z, k).subscribe(x => console.log('combineLatest: ', x));
// concat(x, y, z, k).subscribe(x => console.log('concat: ', x));
// concat(x, y, k, z).subscribe(x => console.log('k在中間的concat: ', x));
}
打印:
往後就每秒打印一次這一組
往後就每秒打印一次 ‘233’
往後就每秒一直打印‘233’,後面的不執行
$test = new Subject();
ngOnInit() {
this.$test.asObservable().subscribe(x => console.log(1111111));
this.$test.next(); // 要對這個subject進行next()才能打印
of(111222).subscribe(x => console.log(x)); // observable直接這樣就可以打印了
}
https://blog.angulartraining.com/rxjs-subjects-a-tutorial-4dcce0e9637f 【RxJs Subjects: A tutorial】
Subject 發射數據
暴露 Subject 時 用 asObservable
Subject
Behavious
普通訂閱者,在數據發射之後創建的話是無法接收到數據的。
什麼時候使用 asObservable()