Pausing and Resuming Timeouts in JavaScript

How to pause and resume a setTimeout() timeout?

You can wrap the window.setTimeout function to create a custom timer that supports pausing and resuming.

var Timer = function(callback, delay) {
    var timerId, start, remaining = delay;

    this.pause = function() {
        window.clearTimeout(timerId);
        timerId = null;
        remaining -= Date.now() - start;
    };

    this.resume = function() {
        if (timerId) {
            return;
        }

        start = Date.now();
        timerId = window.setTimeout(callback, remaining);
    };

    this.resume();
};

How to get the time remaining on the current timeout?

You can use the remaining property of the custom timer to get the time remaining on the current timeout.

var timer = new Timer(function() {
    alert("Done!");
}, 1000);

console.log("Time remaining:", timer.remaining); // Output: 1000

Example usage:

timer.pause();
// Do some stuff...
timer.resume();