getConstructorName(obj) {
		if (obj == null) return undefined;

		let target = obj.prototype;
		if (target && target.constructor && target.constructor.name) {
			return target.constructor.name;
		}
		if (obj.constructor && obj.constructor.name) {
			return obj.constructor.name;
		}
		return undefined;
	}
Get the name of constructor of an object.

@param {Object} obj
@returns {String}