| /** PURE_IMPORTS_START .._operators_pairwise PURE_IMPORTS_END */ |
| import { pairwise as higherOrder } from '../operators/pairwise'; |
| /** |
| * 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 higherOrder()(this); |
| } |
| //# sourceMappingURL=pairwise.js.map |
