subDuration(durationA, durationB) {
		let durA = durationA.match(/^(\d{2,}):(\d{2}):(\d{2}),(\d{3})$/);
		let durB = durationB.match(/^(\d{2,}):(\d{2}):(\d{2}),(\d{3})$/);
		let time = [];
		let formattedTime;

		for (let i = 1; i <= 4; i++) {
			durA[i] = Number(durA[i]);
			durB[i] = Number(durB[i]);
		}

		// milliseconds
		if (durA[4] < durB[4]) {
			durA[4] += 1000;
			durB[3]++;
		}
		time[4] = durA[4] - durB[4];

		// seconds
		if (durA[3] < durB[3]) {
			durA[3] += 60;
			durB[2]++;
		}
		time[3] = durA[3] - durB[3];

		// minutes
		if (durA[2] < durB[2]) {
			durA[2] += 60;
			durB[1]++;
		}
		time[2] = durA[2] - durB[2];

		// hours
		time[1] = durA[1] - durB[1];

		// string format
		formattedTime = `${time[1]}:`;
		if (formattedTime.length < 3) formattedTime = '0' + formattedTime;

		formattedTime += `00${time[2]}:`.slice(-3);
		formattedTime += `00${time[3]},`.slice(-3);

		time[4] = time[4].toString().slice(0,3);
		while (time[4].length < 3) time[4] = '0' + time[4];
		formattedTime += time[4];

		return formattedTime;
	}
Compute (durationA - durationB)

@param {String} durationA
@param {String} durationB
@return {String}