You can not select more than 25 topics
Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
111 lines
3.9 KiB
111 lines
3.9 KiB
2 years ago
|
"use strict";
|
||
|
var __extends = (this && this.__extends) || function (d, b) {
|
||
|
for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
|
||
|
function __() { this.constructor = d; }
|
||
|
d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
|
||
|
};
|
||
|
var Subscriber_1 = require('../Subscriber');
|
||
|
/**
|
||
|
* Counts the number of emissions on the source and emits that number when the
|
||
|
* source completes.
|
||
|
*
|
||
|
* <span class="informal">Tells how many values were emitted, when the source
|
||
|
* completes.</span>
|
||
|
*
|
||
|
* <img src="./img/count.png" width="100%">
|
||
|
*
|
||
|
* `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 <caption>Counts how many seconds have passed before the first click happened</caption>
|
||
|
* 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 <caption>Counts how many odd numbers are there between 1 and 7</caption>
|
||
|
* 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<T>): 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
|
||
|
*/
|
||
|
function count(predicate) {
|
||
|
return function (source) { return source.lift(new CountOperator(predicate, source)); };
|
||
|
}
|
||
|
exports.count = count;
|
||
|
var CountOperator = (function () {
|
||
|
function CountOperator(predicate, source) {
|
||
|
this.predicate = predicate;
|
||
|
this.source = source;
|
||
|
}
|
||
|
CountOperator.prototype.call = function (subscriber, source) {
|
||
|
return source.subscribe(new CountSubscriber(subscriber, this.predicate, this.source));
|
||
|
};
|
||
|
return CountOperator;
|
||
|
}());
|
||
|
/**
|
||
|
* We need this JSDoc comment for affecting ESDoc.
|
||
|
* @ignore
|
||
|
* @extends {Ignored}
|
||
|
*/
|
||
|
var CountSubscriber = (function (_super) {
|
||
|
__extends(CountSubscriber, _super);
|
||
|
function CountSubscriber(destination, predicate, source) {
|
||
|
_super.call(this, destination);
|
||
|
this.predicate = predicate;
|
||
|
this.source = source;
|
||
|
this.count = 0;
|
||
|
this.index = 0;
|
||
|
}
|
||
|
CountSubscriber.prototype._next = function (value) {
|
||
|
if (this.predicate) {
|
||
|
this._tryPredicate(value);
|
||
|
}
|
||
|
else {
|
||
|
this.count++;
|
||
|
}
|
||
|
};
|
||
|
CountSubscriber.prototype._tryPredicate = function (value) {
|
||
|
var result;
|
||
|
try {
|
||
|
result = this.predicate(value, this.index++, this.source);
|
||
|
}
|
||
|
catch (err) {
|
||
|
this.destination.error(err);
|
||
|
return;
|
||
|
}
|
||
|
if (result) {
|
||
|
this.count++;
|
||
|
}
|
||
|
};
|
||
|
CountSubscriber.prototype._complete = function () {
|
||
|
this.destination.next(this.count);
|
||
|
this.destination.complete();
|
||
|
};
|
||
|
return CountSubscriber;
|
||
|
}(Subscriber_1.Subscriber));
|
||
|
//# sourceMappingURL=count.js.map
|