YouTube video duration to seconds

/**
 *  Converts YouTube formatted duration to seconds.
 *
 *  Expects input String of the form "PT#M#S", in which the letters PT indicate
 *  that the value specifies a period of time, and the letters M and S refer to
 *  length in minutes and seconds, respectively. The # characters preceding the
 *  M and S letters are both integers that specify the number of minutes (or
 *  seconds) of the video. For example, a value of PT15M51S indicates that the
 *  video is 15 minutes and 51 seconds long.
 */
var convertTimeToSeconds = function(time) {
    var a = time.match(/\d+H|\d+M|\d+S/g),
        result = 0;

    var d = { 'H': 3600, 'M': 60, 'S': 1 },
        num,
        type;

    for (var i = 0; i < a.length; i++) {
        num = a[i].slice(0, a[i].length - 1);
        type = a[i].slice(a[i].length - 1, a[i].length);

        result += parseInt(num) * d[type];
    }

    return result;
}