SOURCE

String.prototype.endswitch = function(str) {
	if (str === null || str === '' || this.length === 0 || str.length > this.length) {
		return false;
	}
	if (this.substring(this.length - str.length) === str) {
		return true;
	} else {
		return false;
	}
	return true;
}
console.log("abc".endswitch("bc"));