signature: startWith(an: Values): Observable
// RxJS v6+
import { startWith } from 'rxjs/operators';
import { of } from 'rxjs';
//방출 (1,2,3)
const source = of(1, 2, 3);
// 0부터 시작
const example = source.pipe(startWith(0));
//결과: 0,1,2,3
const subscribe = example.subscribe(val => console.log(val));
// RxJS v6+
import { startWith, scan } from 'rxjs/operators';
import { of } from 'rxjs';
//방출 ('World!', 'Goodbye', 'World!')
const source = of('World!', 'Goodbye', 'World!');
// 'Hello'부터 시작하고, 이전값과 현재값 concat하기
const example = source.pipe(
startWith('Hello'),
scan((acc, curr) => `${acc} ${curr}`)
);
/*
결과:
"Hello"
"Hello World!"
"Hello World! Goodbye"
"Hello World! Goodbye World!"
*/
const subscribe = example.subscribe(val => console.log(val));
// RxJS v6+
import { startWith } from 'rxjs/operators';
import { interval } from 'rxjs';
//매 1초마다 값 내보내기
const source = interval(1000);
// -3, -2, -1부터 시작하기
const example = source.pipe(startWith(-3, -2, -1));
//결과: -3, -2, -1, 0, 1, 2....
const subscribe = example.subscribe(val => console.log(val));
