Handlebars helper to transform a time stamp in ms to a nicely formatted "31 minutes ago", "1 hour ago" text.

beautify_date.js

/**
 * Handlebars helper to transform a  time stamp ms to a nicely
 * formatted "31 minutes ago", "1 hour ago" type date.
 */
Handlebars.registerHelper('beautify_date', function(options) {
    var timeAgo = new Date(parseInt(options.fn(this)));
    if (Object.prototype.toString.call(timeAgo) === '[object Date]') {
        if (isNaN(timeAgo.getTime())) {
            return 'Not Valid';
        } else {
            var seconds = Math.floor((new Date() - timeAgo) / 1000),
                intervals = [
                    Math.floor(seconds / 31536000),
                    Math.floor(seconds / 2592000),
                    Math.floor(seconds / 86400),
                    Math.floor(seconds / 3600),
                    Math.floor(seconds / 60)
                ],
                times = [
                    'year',
                    'month',
                    'day',
                    'hour',
                    'minute'
                ];

            var key;
            for(key in intervals) {
                if (intervals[key] > 1)  
                    return intervals[key] + ' ' + times[key] + 's ago';
                else if (intervals[key] === 1) 
                    return intervals[key] + ' ' + times[key] + ' ago';
            }

            return Math.floor(seconds) + ' seconds ago';
        }
    } else {
        return 'Not Valid';
    }
});


// Usage
//  {{#beautify_date}}
//     {{timestamp_ms}}
//  {{/beautify_date}}