| /** PURE_IMPORTS_START .._Subscriber PURE_IMPORTS_END */ |
| 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 __()); |
| }; |
| import { Subscriber } from '../Subscriber'; |
| /** |
| * Groups pairs of consecutive emissions together and emits them as an array of |
| * two values. |
| * |
| * <span class="informal">Puts the current value and previous value together as |
| * an array, and emits that.</span> |
| * |
| * <img src="./img/pairwise.png" width="100%"> |
| * |
| * The Nth emission from the source Observable will cause the output Observable |
| * to emit an array [(N-1)th, Nth] of the previous and the current value, as a |
| * pair. For this reason, `pairwise` emits on the second and subsequent |
| * emissions from the source Observable, but not on the first emission, because |
| * there is no previous value in that case. |
| * |
| * @example <caption>On every click (starting from the second), emit the relative distance to the previous click</caption> |
| * var clicks = Rx.Observable.fromEvent(document, 'click'); |
| * var pairs = clicks.pairwise(); |
| * var distance = pairs.map(pair => { |
| * var x0 = pair[0].clientX; |
| * var y0 = pair[0].clientY; |
| * var x1 = pair[1].clientX; |
| * var y1 = pair[1].clientY; |
| * return Math.sqrt(Math.pow(x0 - x1, 2) + Math.pow(y0 - y1, 2)); |
| * }); |
| * distance.subscribe(x => console.log(x)); |
| * |
| * @see {@link buffer} |
| * @see {@link bufferCount} |
| * |
| * @return {Observable<Array<T>>} An Observable of pairs (as arrays) of |
| * consecutive values from the source Observable. |
| * @method pairwise |
| * @owner Observable |
| */ |
| export function pairwise() { |
| return function (source) { return source.lift(new PairwiseOperator()); }; |
| } |
| var PairwiseOperator = /*@__PURE__*/ (/*@__PURE__*/ function () { |
| function PairwiseOperator() { |
| } |
| PairwiseOperator.prototype.call = function (subscriber, source) { |
| return source.subscribe(new PairwiseSubscriber(subscriber)); |
| }; |
| return PairwiseOperator; |
| }()); |
| /** |
| * We need this JSDoc comment for affecting ESDoc. |
| * @ignore |
| * @extends {Ignored} |
| */ |
| var PairwiseSubscriber = /*@__PURE__*/ (/*@__PURE__*/ function (_super) { |
| __extends(PairwiseSubscriber, _super); |
| function PairwiseSubscriber(destination) { |
| _super.call(this, destination); |
| this.hasPrev = false; |
| } |
| PairwiseSubscriber.prototype._next = function (value) { |
| if (this.hasPrev) { |
| this.destination.next([this.prev, value]); |
| } |
| else { |
| this.hasPrev = true; |
| } |
| this.prev = value; |
| }; |
| return PairwiseSubscriber; |
| }(Subscriber)); |
| //# sourceMappingURL=pairwise.js.map |