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.
77 lines
2.6 KiB
77 lines
2.6 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');
|
||
|
|
/**
|
||
|
|
* 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
|
||
|
|
*/
|
||
|
|
function pairwise() {
|
||
|
|
return function (source) { return source.lift(new PairwiseOperator()); };
|
||
|
|
}
|
||
|
|
exports.pairwise = pairwise;
|
||
|
|
var PairwiseOperator = (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 = (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_1.Subscriber));
|
||
|
|
//# sourceMappingURL=pairwise.js.map
|