93 lines
3.2 KiB
JavaScript
93 lines
3.2 KiB
JavaScript
|
"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');
|
||
|
|
var ArgumentOutOfRangeError_1 = require('../util/ArgumentOutOfRangeError');
|
||
|
|
/**
|
||
|
|
* Skip the last `count` values emitted by the source Observable.
|
||
|
|
*
|
||
|
|
* <img src="./img/skipLast.png" width="100%">
|
||
|
|
*
|
||
|
|
* `skipLast` returns an Observable that accumulates a queue with a length
|
||
|
|
* enough to store the first `count` values. As more values are received,
|
||
|
|
* values are taken from the front of the queue and produced on the result
|
||
|
|
* sequence. This causes values to be delayed.
|
||
|
|
*
|
||
|
|
* @example <caption>Skip the last 2 values of an Observable with many values</caption>
|
||
|
|
* var many = Rx.Observable.range(1, 5);
|
||
|
|
* var skipLastTwo = many.skipLast(2);
|
||
|
|
* skipLastTwo.subscribe(x => console.log(x));
|
||
|
|
*
|
||
|
|
* // Results in:
|
||
|
|
* // 1 2 3
|
||
|
|
*
|
||
|
|
* @see {@link skip}
|
||
|
|
* @see {@link skipUntil}
|
||
|
|
* @see {@link skipWhile}
|
||
|
|
* @see {@link take}
|
||
|
|
*
|
||
|
|
* @throws {ArgumentOutOfRangeError} When using `skipLast(i)`, it throws
|
||
|
|
* ArgumentOutOrRangeError if `i < 0`.
|
||
|
|
*
|
||
|
|
* @param {number} count Number of elements to skip from the end of the source Observable.
|
||
|
|
* @returns {Observable<T>} An Observable that skips the last count values
|
||
|
|
* emitted by the source Observable.
|
||
|
|
* @method skipLast
|
||
|
|
* @owner Observable
|
||
|
|
*/
|
||
|
|
function skipLast(count) {
|
||
|
|
return function (source) { return source.lift(new SkipLastOperator(count)); };
|
||
|
|
}
|
||
|
|
exports.skipLast = skipLast;
|
||
|
|
var SkipLastOperator = (function () {
|
||
|
|
function SkipLastOperator(_skipCount) {
|
||
|
|
this._skipCount = _skipCount;
|
||
|
|
if (this._skipCount < 0) {
|
||
|
|
throw new ArgumentOutOfRangeError_1.ArgumentOutOfRangeError;
|
||
|
|
}
|
||
|
|
}
|
||
|
|
SkipLastOperator.prototype.call = function (subscriber, source) {
|
||
|
|
if (this._skipCount === 0) {
|
||
|
|
// If we don't want to skip any values then just subscribe
|
||
|
|
// to Subscriber without any further logic.
|
||
|
|
return source.subscribe(new Subscriber_1.Subscriber(subscriber));
|
||
|
|
}
|
||
|
|
else {
|
||
|
|
return source.subscribe(new SkipLastSubscriber(subscriber, this._skipCount));
|
||
|
|
}
|
||
|
|
};
|
||
|
|
return SkipLastOperator;
|
||
|
|
}());
|
||
|
|
/**
|
||
|
|
* We need this JSDoc comment for affecting ESDoc.
|
||
|
|
* @ignore
|
||
|
|
* @extends {Ignored}
|
||
|
|
*/
|
||
|
|
var SkipLastSubscriber = (function (_super) {
|
||
|
|
__extends(SkipLastSubscriber, _super);
|
||
|
|
function SkipLastSubscriber(destination, _skipCount) {
|
||
|
|
_super.call(this, destination);
|
||
|
|
this._skipCount = _skipCount;
|
||
|
|
this._count = 0;
|
||
|
|
this._ring = new Array(_skipCount);
|
||
|
|
}
|
||
|
|
SkipLastSubscriber.prototype._next = function (value) {
|
||
|
|
var skipCount = this._skipCount;
|
||
|
|
var count = this._count++;
|
||
|
|
if (count < skipCount) {
|
||
|
|
this._ring[count] = value;
|
||
|
|
}
|
||
|
|
else {
|
||
|
|
var currentIndex = count % skipCount;
|
||
|
|
var ring = this._ring;
|
||
|
|
var oldValue = ring[currentIndex];
|
||
|
|
ring[currentIndex] = value;
|
||
|
|
this.destination.next(oldValue);
|
||
|
|
}
|
||
|
|
};
|
||
|
|
return SkipLastSubscriber;
|
||
|
|
}(Subscriber_1.Subscriber));
|
||
|
|
//# sourceMappingURL=skipLast.js.map
|