123456789101112131415161718192021222324252627282930313233343536373839404142434445464748495051525354555657585960616263646566676869707172737475767778798081828384858687888990919293949596979899100101102103104105 |
- import { isScheduler } from '../util/isScheduler';
- import { of } from './of';
- import { from } from './from';
- import { concatAll } from '../operators/concatAll';
- /* tslint:enable:max-line-length */
- /**
- * Creates an output Observable which sequentially emits all values from 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>
- *
- * <img src="./img/concat.png" width="100%">
- *
- * `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}.
- *
- * @example <caption>Concatenate a timer counting from 0 to 3 with a synchronous sequence from 1 to 10</caption>
- * var timer = Rx.Observable.interval(1000).take(4);
- * var sequence = Rx.Observable.range(1, 10);
- * var result = Rx.Observable.concat(timer, sequence);
- * result.subscribe(x => console.log(x));
- *
- * // results in:
- * // 0 -1000ms-> 1 -1000ms-> 2 -1000ms-> 3 -immediate-> 1 ... 10
- *
- *
- * @example <caption>Concatenate an array of 3 Observables</caption>
- * var timer1 = Rx.Observable.interval(1000).take(10);
- * var timer2 = Rx.Observable.interval(2000).take(6);
- * var timer3 = Rx.Observable.interval(500).take(10);
- * var result = Rx.Observable.concat([timer1, timer2, timer3]); // note that array is passed
- * 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
- *
- *
- * @example <caption>Concatenate the same Observable to repeat it</caption>
- * const timer = Rx.Observable.interval(1000).take(2);
- *
- * Rx.Observable.concat(timer, timer) // concating the same Observable!
- * .subscribe(
- * value => console.log(value),
- * err => {},
- * () => 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}
- *
- * @param {ObservableInput} input1 An input Observable to concatenate with others.
- * @param {ObservableInput} input2 An input Observable to concatenate with others.
- * More than one input Observables may be given as argument.
- * @param {Scheduler} [scheduler=null] An optional IScheduler to schedule each
- * Observable subscription on.
- * @return {Observable} All values of each passed Observable merged into a
- * single Observable, in order, in serial fashion.
- * @static true
- * @name concat
- * @owner Observable
- */
- export function concat(...observables) {
- if (observables.length === 1 || (observables.length === 2 && isScheduler(observables[1]))) {
- return from(observables[0]);
- }
- return concatAll()(of(...observables));
- }
- //# sourceMappingURL=concat.js.map
|