Function compareConstructors

tests/qunit-2.9.2.js:328–354

(a, b)

  	}

  	function compareConstructors(a, b) {
  		var protoA = getProto(a);
  		var protoB = getProto(b);

  		// Comparing constructors is more strict than using `instanceof`
  		if (a.constructor === b.constructor) {
  			return true;
  		}

  		// Ref #851
  		// If the obj prototype descends from a null constructor, treat it
  		// as a null prototype.
  		if (protoA && protoA.constructor === null) {
  			protoA = null;
  		}
  		if (protoB && protoB.constructor === null) {
  			protoB = null;
  		}

  		// Allow objects with no prototype to be equivalent to
  		// objects with Object as their constructor.
  		if (protoA === null && protoB === Object.prototype || protoB === null && protoA === Object.prototype) {
  			return true;
  		}

  		return false;
  	}

  	function getRegExpFlags(regexp) {
  		return "flags" in regexp ? regexp.flags : regexp.toString().match(/[gimuy]*$/)[0];