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Diffstat (limited to 'node_modules/rxjs/src/internal/observable/concat.ts')
| -rw-r--r-- | node_modules/rxjs/src/internal/observable/concat.ts | 115 |
1 files changed, 115 insertions, 0 deletions
diff --git a/node_modules/rxjs/src/internal/observable/concat.ts b/node_modules/rxjs/src/internal/observable/concat.ts new file mode 100644 index 0000000..edbaa31 --- /dev/null +++ b/node_modules/rxjs/src/internal/observable/concat.ts @@ -0,0 +1,115 @@ +import { Observable } from '../Observable'; +import { ObservableInputTuple, SchedulerLike } from '../types'; +import { concatAll } from '../operators/concatAll'; +import { popScheduler } from '../util/args'; +import { from } from './from'; + +export function concat<T extends readonly unknown[]>(...inputs: [...ObservableInputTuple<T>]): Observable<T[number]>; +export function concat<T extends readonly unknown[]>( + ...inputsAndScheduler: [...ObservableInputTuple<T>, SchedulerLike] +): Observable<T[number]>; + +/** + * Creates an output Observable which sequentially emits all values from the first given + * Observable and then moves on to the next. + * + * <span class="informal">Concatenates multiple Observables together by + * sequentially emitting their values, one Observable after the other.</span> + * + *  + * + * `concat` joins multiple Observables together, by subscribing to them one at a time and + * merging their results into the output Observable. You can pass either an array of + * Observables, or put them directly as arguments. Passing an empty array will result + * in Observable that completes immediately. + * + * `concat` will subscribe to first input Observable and emit all its values, without + * changing or affecting them in any way. When that Observable completes, it will + * subscribe to then next Observable passed and, again, emit its values. This will be + * repeated, until the operator runs out of Observables. When last input Observable completes, + * `concat` will complete as well. At any given moment only one Observable passed to operator + * emits values. If you would like to emit values from passed Observables concurrently, check out + * {@link merge} instead, especially with optional `concurrent` parameter. As a matter of fact, + * `concat` is an equivalent of `merge` operator with `concurrent` parameter set to `1`. + * + * Note that if some input Observable never completes, `concat` will also never complete + * and Observables following the one that did not complete will never be subscribed. On the other + * hand, if some Observable simply completes immediately after it is subscribed, it will be + * invisible for `concat`, which will just move on to the next Observable. + * + * If any Observable in chain errors, instead of passing control to the next Observable, + * `concat` will error immediately as well. Observables that would be subscribed after + * the one that emitted error, never will. + * + * If you pass to `concat` the same Observable many times, its stream of values + * will be "replayed" on every subscription, which means you can repeat given Observable + * as many times as you like. If passing the same Observable to `concat` 1000 times becomes tedious, + * you can always use {@link repeat}. + * + * ## Examples + * + * Concatenate a timer counting from 0 to 3 with a synchronous sequence from 1 to 10 + * + * ```ts + * import { interval, take, range, concat } from 'rxjs'; + * + * const timer = interval(1000).pipe(take(4)); + * const sequence = range(1, 10); + * const result = concat(timer, sequence); + * result.subscribe(x => console.log(x)); + * + * // results in: + * // 0 -1000ms-> 1 -1000ms-> 2 -1000ms-> 3 -immediate-> 1 ... 10 + * ``` + * + * Concatenate 3 Observables + * + * ```ts + * import { interval, take, concat } from 'rxjs'; + * + * const timer1 = interval(1000).pipe(take(10)); + * const timer2 = interval(2000).pipe(take(6)); + * const timer3 = interval(500).pipe(take(10)); + * + * const result = concat(timer1, timer2, timer3); + * result.subscribe(x => console.log(x)); + * + * // results in the following: + * // (Prints to console sequentially) + * // -1000ms-> 0 -1000ms-> 1 -1000ms-> ... 9 + * // -2000ms-> 0 -2000ms-> 1 -2000ms-> ... 5 + * // -500ms-> 0 -500ms-> 1 -500ms-> ... 9 + * ``` + * + * Concatenate the same Observable to repeat it + * + * ```ts + * import { interval, take, concat } from 'rxjs'; + * + * const timer = interval(1000).pipe(take(2)); + * + * concat(timer, timer) // concatenating the same Observable! + * .subscribe({ + * next: value => console.log(value), + * complete: () => console.log('...and it is done!') + * }); + * + * // Logs: + * // 0 after 1s + * // 1 after 2s + * // 0 after 3s + * // 1 after 4s + * // '...and it is done!' also after 4s + * ``` + * + * @see {@link concatAll} + * @see {@link concatMap} + * @see {@link concatMapTo} + * @see {@link startWith} + * @see {@link endWith} + * + * @param args `ObservableInput`s to concatenate. + */ +export function concat(...args: any[]): Observable<unknown> { + return concatAll()(from(args, popScheduler(args))); +} |
