momentjs countdown

gistfile1.js

//bug: in the following case 1d 00h 00m 25s it would not show "00m" since it only checks previous time component

var x = moment()
    .add(1, 'month')
    .add(1, 'day')
    .add(1, 'hour')
    .add(1, 'minute')
    .add(10, 'seconds');

function format(duration) {
    var formattedDuration = '';
    //todo restuta: remove that comment if it's no longer relevant
    //all except seconds, since we handle them separately, because they require special formatting
    var timeComponents = ['y', 'M', 'd', 'h', 'm', 's']; 
    
    var previousTimeComponent = null;

    for (timeComponent of timeComponents) {

        
            var shouldShowZeroes = false;

            /*  checking if previous time compoenent is 0 or now so in case when it's not 
                e.g. 1h 00m 22s we would still show '00' for minutes
                and in case it _is zero we would not show anything
                e.g. if ther are not hours and no minutes we would how just 22s and not 00h 00m 22s
             */
            if (previousTimeComponent && duration.get(previousTimeComponent)) {
                shouldShowZeroes = true;
            }
            
            if (!duration.get(timeComponent) && shouldShowZeroes) {
                formattedDuration += '00' + timeComponent + ' ';     
            } else if (duration.get(timeComponent)) {
                formattedDuration += duration.get(timeComponent) + timeComponent + ' ';                     
            } else {
                //do not print anything
            }
               
        
        var previousTimeComponent = timeComponent;    
    }

    //formattedDuration += ' ' + (duration.seconds() || '00') + 's';

    return formattedDuration; 
}

function countdownStep(timeLeft, intervalId, invervalInMs, elementToWriteTo) {

    timeLeft.subtract(invervalInMs, 'milliseconds');
    console.log(timeLeft.humanize());
    elementToWriteTo.innerText = (format(timeLeft));

    if (timeLeft.asMilliseconds() <= 0) {
        clearInterval(intervalId);
    }
}

//run first timer
var invervalInMs = 1000;
var timeLeft = moment.duration(x - moment());

var intervalId = setInterval(function() {
    var elementToWriteTo = document.querySelector('.docs-section-title');    
    countdownStep(timeLeft, intervalId, invervalInMs, elementToWriteTo);
}, invervalInMs / 100);