/*
*Define color based on color contrast
*/
String.prototype.contrast = function() {
	var t = this.toString().replace(/^#?([a-f\d])([a-f\d])([a-f\d])$/i, function(t, n, r, a) {
			return n + n + r + r + a + a
		}),
		n = /^#?([a-f\d]{2})([a-f\d]{2})([a-f\d]{2})$/i.exec(t);
	return out = n ? {
		r: parseInt(n[1], 16),
		g: parseInt(n[2], 16),
		b: parseInt(n[3], 16)
	} : null, out = Math.round((299 * out.r + 587 * out.g + 114 * out.b) / 1e3), contrast = out < 125 ? "#fff" : "#000", contrast
};

/** EG: **/
let hexColor = "#fff"
console.log({contrast:hexColor.contrast()});