How to parse a duration string into seconds with Javascript?

Question

I\'m trying to parse a user input string for duration (into seconds) with Javascript.

Here are some example inputs that I\'d like to be able to deal with:

Answer 1

A more general version of the accepted answer that accepts months and seconds as well.

const getSeconds = str => {
    let seconds = 0;
    let months = str.match(/(\d+)\s*M/);
    let days = str.match(/(\d+)\s*D/);
    let hours = str.match(/(\d+)\s*h/);
    let minutes = str.match(/(\d+)\s*m/);
    let secs = str.match(/(\d+)\s*s/);
    if (months) { seconds += parseInt(months[1])*86400*30; }
    if (days) { seconds += parseInt(days[1])*86400; }
    if (hours) { seconds += parseInt(hours[1])*3600; }
    if (minutes) { seconds += parseInt(minutes[1])*60; }
    if (secs) { seconds += parseInt(secs[1]); }
    return seconds;
};