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111 lines
4.8 KiB
111 lines
4.8 KiB
"use strict"; |
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var isScheduler_1 = require('../util/isScheduler'); |
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var of_1 = require('./of'); |
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var from_1 = require('./from'); |
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var concatAll_1 = require('../operators/concatAll'); |
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/* tslint:enable:max-line-length */ |
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/** |
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* Creates an output Observable which sequentially emits all values from given |
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* Observable and then moves on to the next. |
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* |
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* <span class="informal">Concatenates multiple Observables together by |
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* sequentially emitting their values, one Observable after the other.</span> |
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* |
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* <img src="./img/concat.png" width="100%"> |
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* |
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* `concat` joins multiple Observables together, by subscribing to them one at a time and |
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* merging their results into the output Observable. You can pass either an array of |
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* Observables, or put them directly as arguments. Passing an empty array will result |
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* in Observable that completes immediately. |
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* |
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* `concat` will subscribe to first input Observable and emit all its values, without |
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* changing or affecting them in any way. When that Observable completes, it will |
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* subscribe to then next Observable passed and, again, emit its values. This will be |
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* repeated, until the operator runs out of Observables. When last input Observable completes, |
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* `concat` will complete as well. At any given moment only one Observable passed to operator |
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* emits values. If you would like to emit values from passed Observables concurrently, check out |
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* {@link merge} instead, especially with optional `concurrent` parameter. As a matter of fact, |
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* `concat` is an equivalent of `merge` operator with `concurrent` parameter set to `1`. |
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* |
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* Note that if some input Observable never completes, `concat` will also never complete |
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* and Observables following the one that did not complete will never be subscribed. On the other |
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* hand, if some Observable simply completes immediately after it is subscribed, it will be |
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* invisible for `concat`, which will just move on to the next Observable. |
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* |
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* If any Observable in chain errors, instead of passing control to the next Observable, |
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* `concat` will error immediately as well. Observables that would be subscribed after |
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* the one that emitted error, never will. |
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* |
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* If you pass to `concat` the same Observable many times, its stream of values |
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* will be "replayed" on every subscription, which means you can repeat given Observable |
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* as many times as you like. If passing the same Observable to `concat` 1000 times becomes tedious, |
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* you can always use {@link repeat}. |
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* |
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* @example <caption>Concatenate a timer counting from 0 to 3 with a synchronous sequence from 1 to 10</caption> |
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* var timer = Rx.Observable.interval(1000).take(4); |
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* var sequence = Rx.Observable.range(1, 10); |
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* var result = Rx.Observable.concat(timer, sequence); |
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* result.subscribe(x => console.log(x)); |
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* |
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* // results in: |
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* // 0 -1000ms-> 1 -1000ms-> 2 -1000ms-> 3 -immediate-> 1 ... 10 |
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* |
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* |
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* @example <caption>Concatenate an array of 3 Observables</caption> |
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* var timer1 = Rx.Observable.interval(1000).take(10); |
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* var timer2 = Rx.Observable.interval(2000).take(6); |
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* var timer3 = Rx.Observable.interval(500).take(10); |
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* var result = Rx.Observable.concat([timer1, timer2, timer3]); // note that array is passed |
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* result.subscribe(x => console.log(x)); |
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* |
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* // results in the following: |
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* // (Prints to console sequentially) |
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* // -1000ms-> 0 -1000ms-> 1 -1000ms-> ... 9 |
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* // -2000ms-> 0 -2000ms-> 1 -2000ms-> ... 5 |
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* // -500ms-> 0 -500ms-> 1 -500ms-> ... 9 |
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* |
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* |
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* @example <caption>Concatenate the same Observable to repeat it</caption> |
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* const timer = Rx.Observable.interval(1000).take(2); |
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* |
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* Rx.Observable.concat(timer, timer) // concating the same Observable! |
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* .subscribe( |
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* value => console.log(value), |
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* err => {}, |
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* () => console.log('...and it is done!') |
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* ); |
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* |
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* // Logs: |
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* // 0 after 1s |
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* // 1 after 2s |
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* // 0 after 3s |
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* // 1 after 4s |
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* // "...and it is done!" also after 4s |
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* |
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* @see {@link concatAll} |
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* @see {@link concatMap} |
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* @see {@link concatMapTo} |
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* |
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* @param {ObservableInput} input1 An input Observable to concatenate with others. |
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* @param {ObservableInput} input2 An input Observable to concatenate with others. |
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* More than one input Observables may be given as argument. |
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* @param {Scheduler} [scheduler=null] An optional IScheduler to schedule each |
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* Observable subscription on. |
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* @return {Observable} All values of each passed Observable merged into a |
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* single Observable, in order, in serial fashion. |
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* @static true |
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* @name concat |
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* @owner Observable |
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*/ |
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function concat() { |
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var observables = []; |
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for (var _i = 0; _i < arguments.length; _i++) { |
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observables[_i - 0] = arguments[_i]; |
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} |
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if (observables.length === 1 || (observables.length === 2 && isScheduler_1.isScheduler(observables[1]))) { |
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return from_1.from(observables[0]); |
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} |
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return concatAll_1.concatAll()(of_1.of.apply(void 0, observables)); |
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} |
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exports.concat = concat; |
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//# sourceMappingURL=concat.js.map
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