Optimized the most common use-case likely with Topiarist (verifying a…

…rguments using isA()) so that it's now ~2.5 times slower than doing the same check manually, rather than being ~25 times slower, as was the case before. To achive this I did have to relax the argument checking performed, but this actuallly resulted in the browser throwing a clearer error message than what Topiarist was producing anyway.

lib/topiarist.js

@@ -398,19 +398,17 @@
 	 *  or is null, false otherwise.
 	 */
 	function isA(instance, parent) {
+		if(instance == null) {
+			return false;
+		}
+
 		// sneaky edge case where we're checking against an object literal we've mixed in or against a prototype of
 		//  something.
 		if (typeof parent === 'object' && parent.hasOwnProperty('constructor')) {
 			parent = parent.constructor;
 		}
 
-		assertArgumentOfType('function', parent, ERROR_MESSAGES.NOT_CONSTRUCTOR, 'Parent', 'isA');
-
-		if (instance == null) {
-			return false;
-		}
-
-		if (instance instanceof parent) {
+		if((instance.constructor === parent) || (instance instanceof parent)) {
 			return true;
 		}
 

package.json

@@ -1,6 +1,6 @@
 {
 	"name": "topiarist",
-	"version": "0.1.0",
+	"version": "0.1.1",
 	"author": "kybernetikos <[email protected]>",
 	"description": "Topiarist provides tree and shape-based type verification for JavaScript.",
 	"main": "./lib/topiarist.js",

spec/IsASpec.js

@@ -47,7 +47,7 @@ describe("topiarist.isA", function() {
 	it('throws an error if the potential assignee is not a constructor.', function() {
 		expect( function() {
 			topiarist.isA(instance, 34);
-		}).toThrow(err.NOT_CONSTRUCTOR('Parent', 'isA', 'number'));
+		}).toThrow();
 	});
 
 	it('returns false for a null instance.', function() {
@@ -85,4 +85,4 @@ describe("topiarist.isA", function() {
 	it('returns true for an instance and a mixin that was defined without a constructor.', function() {
 		expect( topiarist.isA(instance, ObjMixin)).toBe( true );
 	});
-});
+});