48 lines
1.8 KiB
JavaScript
48 lines
1.8 KiB
JavaScript
|
/** PURE_IMPORTS_START .._observable_ArrayObservable,.._observable_ScalarObservable,.._observable_EmptyObservable,.._observable_concat,.._util_isScheduler PURE_IMPORTS_END */
|
||
|
|
import { ArrayObservable } from '../observable/ArrayObservable';
|
||
|
|
import { ScalarObservable } from '../observable/ScalarObservable';
|
||
|
|
import { EmptyObservable } from '../observable/EmptyObservable';
|
||
|
|
import { concat as concatStatic } from '../observable/concat';
|
||
|
|
import { isScheduler } from '../util/isScheduler';
|
||
|
|
/* tslint:enable:max-line-length */
|
||
|
|
/**
|
||
|
|
* Returns an Observable that emits the items you specify as arguments before it begins to emit
|
||
|
|
* items emitted by the source Observable.
|
||
|
|
*
|
||
|
|
* <img src="./img/startWith.png" width="100%">
|
||
|
|
*
|
||
|
|
* @param {...T} values - Items you want the modified Observable to emit first.
|
||
|
|
* @param {Scheduler} [scheduler] - A {@link IScheduler} to use for scheduling
|
||
|
|
* the emissions of the `next` notifications.
|
||
|
|
* @return {Observable} An Observable that emits the items in the specified Iterable and then emits the items
|
||
|
|
* emitted by the source Observable.
|
||
|
|
* @method startWith
|
||
|
|
* @owner Observable
|
||
|
|
*/
|
||
|
|
export function startWith() {
|
||
|
|
var array = [];
|
||
|
|
for (var _i = 0; _i < arguments.length; _i++) {
|
||
|
|
array[_i - 0] = arguments[_i];
|
||
|
|
}
|
||
|
|
return function (source) {
|
||
|
|
var scheduler = array[array.length - 1];
|
||
|
|
if (isScheduler(scheduler)) {
|
||
|
|
array.pop();
|
||
|
|
}
|
||
|
|
else {
|
||
|
|
scheduler = null;
|
||
|
|
}
|
||
|
|
var len = array.length;
|
||
|
|
if (len === 1) {
|
||
|
|
return concatStatic(new ScalarObservable(array[0], scheduler), source);
|
||
|
|
}
|
||
|
|
else if (len > 1) {
|
||
|
|
return concatStatic(new ArrayObservable(array, scheduler), source);
|
||
|
|
}
|
||
|
|
else {
|
||
|
|
return concatStatic(new EmptyObservable(scheduler), source);
|
||
|
|
}
|
||
|
|
};
|
||
|
|
}
|
||
|
|
//# sourceMappingURL=startWith.js.map
|