xstream/extra/concat.js

An extremely intuitive, small, and fast functional reactive stream library for JavaScript

"use strict";
var core_1 = require('../core');
var ConcatProducer = (function () {
    function ConcatProducer(streams) {
        this.streams = streams;
        this.type = 'concat';
        this.out = null;
        this.i = 0;
    }
    ConcatProducer.prototype._start = function (out) {
        this.out = out;
        this.streams[this.i]._add(this);
    };
    ConcatProducer.prototype._stop = function () {
        var streams = this.streams;
        if (this.i < streams.length) {
            streams[this.i]._remove(this);
        }
        this.i = 0;
        this.out = null;
    };
    ConcatProducer.prototype._n = function (t) {
        var u = this.out;
        if (!u)
            return;
        u._n(t);
    };
    ConcatProducer.prototype._e = function (err) {
        var u = this.out;
        if (!u)
            return;
        u._e(err);
    };
    ConcatProducer.prototype._c = function () {
        var u = this.out;
        if (!u)
            return;
        var streams = this.streams;
        streams[this.i]._remove(this);
        if (++this.i < streams.length) {
            streams[this.i]._add(this);
        }
        else {
            u._c();
        }
    };
    return ConcatProducer;
}());
/**
 * Puts one stream after the other. *concat* is a factory that takes multiple
 * streams as arguments, and starts the `n+1`-th stream only when the `n`-th
 * stream has completed. It concatenates those streams together.
 *
 * Marble diagram:
 *
 * ```text
 * --1--2---3---4-|
 * ...............--a-b-c--d-|
 *           concat
 * --1--2---3---4---a-b-c--d-|
 * ```
 *
 * Example:
 *
 * ```js
 * import concat from 'xstream/extra/concat'
 *
 * const streamA = xs.of('a', 'b', 'c')
 * const streamB = xs.of(10, 20, 30)
 * const streamC = xs.of('X', 'Y', 'Z')
 *
 * const outputStream = concat(streamA, streamB, streamC)
 *
 * outputStream.addListener({
 *   next: (x) => console.log(x),
 *   error: (err) => console.error(err),
 *   complete: () => console.log('concat completed'),
 * })
 * ```
 *
 * @factory true
 * @param {Stream} stream1 A stream to concatenate together with other streams.
 * @param {Stream} stream2 A stream to concatenate together with other streams. Two
 * or more streams may be given as arguments.
 * @return {Stream}
 */
function concat() {
    var streams = [];
    for (var _i = 0; _i < arguments.length; _i++) {
        streams[_i - 0] = arguments[_i];
    }
    return new core_1.Stream(new ConcatProducer(streams));
}
Object.defineProperty(exports, "__esModule", { value: true });
exports.default = concat;
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