I'm looking for a function that can convert 1 day to 86400000 or 20 min to 1200000 . I'm going from a readable string to a number of ms

Something like:

var key = { s: 1000, m:1000*60, h:1000*60*60, d: 1000*60*60*24, ... },
    m = str.match((\d+) (\w)),
    result = m[1] * (key[m[2]] || 1); 

I'm looking for a function that can convert 1 day to 86400000 or 20 min to 1200000 . I'm going from a readable string to a number of ms

Something like:

var key = { s: 1000, m:1000*60, h:1000*60*60, d: 1000*60*60*24, ... },
    m = str.match((\d+) (\w)),
    result = m[1] * (key[m[2]] || 1); 

• javascript
• date

• 1 You might want to be looking into using the built-in Date object for this kind of stuff, as it can cope with a lot of stuff such as leap years and daylight saving that this approach can't deal with. – GordonM Commented Feb 25, 2011 at 14:40

4 Answers 4

The code you have should work pretty well. I took the basic idea and threw together a more flexible function that can bine units. It's extremely relaxed about what it accepts, but you could make it more strict if you wanted to.

(function() {
    var units = {
        ms: 1/1000,

        m: 60,
        min: 60, mins: 60,
        minute: 60, minutes: 60,

        h: 60*60,
        hr: 60*60, hrs: 60*60,
        hour: 60*60, hours: 60*60,

        d: 60*60*24,
        day: 60*60*24, days: 60*60*24,
    };

    Date.parseInterval = function(interval) {
        var seconds = 0;
        interval.replace(/(\d+(?:\.\d*)?)\s*([a-z]+)?/ig, function($0, number, unit) {
            if (unit) {
                number *= units[unit.toLowerCase()] || 1;
            }
            seconds += +number;
        });
        return seconds * 1000;
    };
})();

console.log(Date.parseInterval('1 day') === 86400000);
console.log(Date.parseInterval('20 min') === 1200000);
console.log(Date.parseInterval('1 day, 3 hours, and 22.5 seconds') === 97222500);

strToMs = function(str) {
    var multiplier = {
        ms: 1, mil: 1, s:1000, sec: 1000, min: 1000*60,
        hr: 1000*60*60, hrs: 1000*60*60, hou: 1000*60*60,
        d: 1000*60*60*24, day: 1000*60*60*24, mon: 1000*60*60*24*30,
        y: 1000*60*60*24*386.25, yea: 1000*60*60*24*386.25
    },
    num = str.match(/\d+/), units = str.match(/[a-z]{1,3}/i)
    return num * (multiplier[units] || 1);
}

DEMO

The built-in Date object can handle a lot of stuff. Otherwise, something like http://www.datejs./ may be helpful

I've had success in the past using the datejs library for dates.

It seems to support parsing strings like now + 20 min, so at worst you could subtract now (or any fixed Date doesn't seem to support this), and then call getMilliseconds() on that.