setTimeout and setInterval in gjs

The GLib.timeout_add function is the GJS equivalent to both setTimeout and setInterval. It calls a given function repeatedly (such as func) at given intervals until it returns a falsy value. It returns a GLib Source id, which just like clearTimeout or clearInterval can be removed with the static GLib.Source.remove function.

The following code is licensed under the GNU Lesser General Public License v3.0 or later:

/* exported clearTimeout clearInterval setTimeout setInterval */

 * Copyright 2020 Dafne Kiyui
 * This program is free software: you can redistribute it and/or modify
 * it under the terms of the GNU Lesser General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * GNU Lesser General Public License for more details.
 * You should have received a copy of the GNU Lesser General Public License
 * along with this program.  If not, see <>.
const {GLib} =;

var clearTimeout, clearInterval;
clearTimeout = clearInterval = GLib.Source.remove;

function setTimeout(func, delay, ...args) {
    const wrappedFunc = () => {
        func.apply(this, args);
    return GLib.timeout_add(GLib.PRIORITY_DEFAULT, delay, wrappedFunc);

function setInterval(func, delay, ...args) {
    const wrappedFunc = () => {
        return func.apply(this, args) || true;
    return GLib.timeout_add(GLib.PRIORITY_DEFAULT, delay, wrappedFunc);

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For the sake of trivia, according to MDN, both setTimeout() and setInterval() share the same pool of IDs. As such, both clearTimeout() and clearInterval() can be used interchangeably. This makes the above code pretty compatible and standards compliant 😉