Hi, I would like to understand the working of the Function#methodize method and yes, I have read this post: http://groups.google.com/group/prototype-scriptaculous/browse_thread/thread/d9c5444eaa66bdaf/e8287ff38260f0a9?lnk=gst&q=methodize#e8287ff38260f0a9 , but it is still unclear for me.
I broke it down to something like a minimal case like this: <!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http:// www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"> <html xmlns="http://www.w3.org/1999/xhtml";> <head> <meta http-equiv="Content-type" content="text/ html;charset=iso-8859-1" /> <title>Test methodize</title> <script language="javascript" type="text/ javascript">Function.prototype.update = function(array, args){ var array_length = array.length, length = args.length; while(length --){ array[array_length + length] = args[length]; } return array; } /* Function.prototype.methodize = function(){ if(this._methodized){ return this._methodized;} var __method = this; return this._methodized = function(){ console.log(this); var a = Function.prototype.update([], arguments); return __method.apply(this, a); }; } */ Function.prototype.methodize = function(){ if(this._methodized){ return this._methodized;} var __method = this; return this._methodized = function(){ console.log(this); var a = Function.prototype.update([this], arguments); return __method.apply(null, a); }; } window.addEventListener('load', function(){ var obj_a = { value : 2, name : 'obj_a' }; var obj_b = { value : 5, name : 'obj_b' } var multiplier = function(times){ times = isNaN(times) ? 2 : times; if(typeof this.value != 'undefined'){ return this.value * times; } else{ alert(this + ': does not have a value property!');} }; obj_a.multiply = multiplier.methodize(); console.log(obj_a.multiply(3)); console.log(obj_a.multiply(10)); obj_b.multiply = multiplier.methodize(); console.log(obj_b.multiply(5)); }, false); </script> </head> <body> <div>Nothing to see here</div> </body> </html> If you run the above code, you will get a series of alert messages as you should, I think. In my understanding calling methodize on any function for the first time means creating a static _methodized method on that particular function that did not exist so far, while any later call to it returns a reference to this static method regardless where the call originates from. if(this._methodized){ return this._methodized;} return this._methodized = function(){} Through assignments any number of objects can have any named methods to refer to _methodized, but the ‘this’ keyword inside it will always points to that particular object from which I am calling it. Following this argumentation replacing methodize with this makes the above code work as expected: Function.prototype.methodize = function(){ if(this._methodized){ return this._methodized;} var __method = this; return this._methodized = function(){ console.log(this); var a = Function.prototype.update([], arguments); return __method.apply(this, a); }; } Could someone explain why and how the null value for the thisArg argument in the original version is used if it is always resolved to the window object in a browser and how methodize works? -- You received this message because you are subscribed to the Google Groups "Prototype & script.aculo.us" group. To post to this group, send email to prototype-scriptaculous@googlegroups.com. To unsubscribe from this group, send email to prototype-scriptaculous+unsubscr...@googlegroups.com. For more options, visit this group at http://groups.google.com/group/prototype-scriptaculous?hl=en.
