import { count as higherOrder } from '../operators/count'; /** * Counts the number of emissions on the source and emits that number when the * source completes. * * Tells how many values were emitted, when the source * completes. * * * * `count` transforms an Observable that emits values into an Observable that * emits a single value that represents the number of values emitted by the * source Observable. If the source Observable terminates with an error, `count` * will pass this error notification along without emitting a value first. If * the source Observable does not terminate at all, `count` will neither emit * a value nor terminate. This operator takes an optional `predicate` function * as argument, in which case the output emission will represent the number of * source values that matched `true` with the `predicate`. * * @example Counts how many seconds have passed before the first click happened * var seconds = Rx.Observable.interval(1000); * var clicks = Rx.Observable.fromEvent(document, 'click'); * var secondsBeforeClick = seconds.takeUntil(clicks); * var result = secondsBeforeClick.count(); * result.subscribe(x => console.log(x)); * * @example Counts how many odd numbers are there between 1 and 7 * var numbers = Rx.Observable.range(1, 7); * var result = numbers.count(i => i % 2 === 1); * result.subscribe(x => console.log(x)); * * // Results in: * // 4 * * @see {@link max} * @see {@link min} * @see {@link reduce} * * @param {function(value: T, i: number, source: Observable): boolean} [predicate] A * boolean function to select what values are to be counted. It is provided with * arguments of: * - `value`: the value from the source Observable. * - `index`: the (zero-based) "index" of the value from the source Observable. * - `source`: the source Observable instance itself. * @return {Observable} An Observable of one number that represents the count as * described above. * @method count * @owner Observable */ export function count(predicate) { return higherOrder(predicate)(this); } //# sourceMappingURL=count.js.map