xstream
Version:
An extremely intuitive, small, and fast functional reactive stream library for JavaScript
120 lines • 8.55 kB
JavaScript
;
Object.defineProperty(exports, "__esModule", { value: true });
exports.DropRepeatsOperator = void 0;
var index_1 = require("../index");
var empty = {};
var DropRepeatsOperator = /** @class */ (function () {
function DropRepeatsOperator(ins, fn) {
this.ins = ins;
this.type = 'dropRepeats';
this.out = null;
this.v = empty;
this.isEq = fn ? fn : function (x, y) { return x === y; };
}
DropRepeatsOperator.prototype._start = function (out) {
this.out = out;
this.ins._add(this);
};
DropRepeatsOperator.prototype._stop = function () {
this.ins._remove(this);
this.out = null;
this.v = empty;
};
DropRepeatsOperator.prototype._n = function (t) {
var u = this.out;
if (!u)
return;
var v = this.v;
if (v !== empty && this.isEq(t, v))
return;
this.v = t;
u._n(t);
};
DropRepeatsOperator.prototype._e = function (err) {
var u = this.out;
if (!u)
return;
u._e(err);
};
DropRepeatsOperator.prototype._c = function () {
var u = this.out;
if (!u)
return;
u._c();
};
return DropRepeatsOperator;
}());
exports.DropRepeatsOperator = DropRepeatsOperator;
/**
* Drops consecutive duplicate values in a stream.
*
* Marble diagram:
*
* ```text
* --1--2--1--1--1--2--3--4--3--3|
* dropRepeats
* --1--2--1--------2--3--4--3---|
* ```
*
* Example:
*
* ```js
* import dropRepeats from 'xstream/extra/dropRepeats'
*
* const stream = xs.of(1, 2, 1, 1, 1, 2, 3, 4, 3, 3)
* .compose(dropRepeats())
*
* stream.addListener({
* next: i => console.log(i),
* error: err => console.error(err),
* complete: () => console.log('completed')
* })
* ```
*
* ```text
* > 1
* > 2
* > 1
* > 2
* > 3
* > 4
* > 3
* > completed
* ```
*
* Example with a custom isEqual function:
*
* ```js
* import dropRepeats from 'xstream/extra/dropRepeats'
*
* const stream = xs.of('a', 'b', 'a', 'A', 'B', 'b')
* .compose(dropRepeats((x, y) => x.toLowerCase() === y.toLowerCase()))
*
* stream.addListener({
* next: i => console.log(i),
* error: err => console.error(err),
* complete: () => console.log('completed')
* })
* ```
*
* ```text
* > a
* > b
* > a
* > B
* > completed
* ```
*
* @param {Function} isEqual An optional function of type
* `(x: T, y: T) => boolean` that takes an event from the input stream and
* checks if it is equal to previous event, by returning a boolean.
* @return {Stream}
*/
function dropRepeats(isEqual) {
if (isEqual === void 0) { isEqual = void 0; }
return function dropRepeatsOperator(ins) {
return new index_1.Stream(new DropRepeatsOperator(ins, isEqual));
};
}
exports.default = dropRepeats;
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