Explanations for each step of isPlainObject

rwaldron · rwaldron · commit 3746bf8feb30 · 2012-12-26T13:34:38.000-05:00
Signed-off-by: Rick Waldron &lt;waldron.rick@gmail.com&gt;
diff --git a/src/core.js b/src/core.js
@@ -412,12 +412,17 @@ jQuery.extend({
 	},
 
 	isPlainObject: function( obj ) {
-		// Not plain objects: params that are not [[Class]] "[object Object]", DOM nodes, window
+		// Not plain objects:
+		// - Any object or value whose internal [[Class]] property is not "[object Object]"
+		// - DOM nodes
+		// - window
 		if ( jQuery.type( obj ) !== "object" || obj.nodeType || jQuery.isWindow( obj ) ) {
 			return false;
 		}
 
 		// Support: Firefox >16
+		// The try/catch supresses exceptions thrown when attempting to access
+		// the "constructor" property of certain host objects, ie. |window.location|
 		try {
 			if ( obj.constructor &&
 					!core_hasOwn.call( obj.constructor.prototype, "isPrototypeOf" ) ) {
@@ -427,6 +432,8 @@ jQuery.extend({
 			return false;
 		}
 
+		// If the function hasn't returned already, we're confident that
+		// |obj| is a plain object, created by {} or constructed with new Object
 		return true;
 	},
 
