sub-events/ext/from-interval.js

Lightweight, strongly-typed events, with monitored subscriptions.

"use strict";
Object.defineProperty(exports, "__esModule", { value: true });
exports.fromInterval = fromInterval;
var src_1 = require("../dist/src");
/**
 * Creates a time-interval event:
 *
 * - The interval re-starts when the first subscriber registers;
 * - The interval stops when the last subscription is cancelled.
 */
function fromInterval(timeout, options) {
    var sec = new src_1.SubEventCount();
    var timer;
    sec.onCount.subscribe(function (info) {
        var start = info.prevCount === 0; // fresh start
        var stop = info.newCount === 0; // no subscriptions left
        if (start) {
            timer = setInterval(function () {
                sec.emit(undefined, options);
            }, timeout);
        }
        else {
            if (stop) {
                clearInterval(timer);
            }
        }
    });
    return sec;
}