Function#methodize() → Function

Wraps the function inside another function that, when called, pushes this to the original function as the first argument (with any further arguments following it).

The methodize method transforms the original function that has an explicit first argument to a function that passes this (the current context) as an implicit first argument at call time. It is useful when we want to transform a function that takes an object to a method of that object or its prototype, shortening its signature by one argument.

Example

// A function that sets a name on a target object
function setName(target, name) {
  target.name = name;
}
 // Use it
obj = {};
setName(obj, 'Fred');
obj.name;
// -> "Fred"
 // Make it a method of the object
obj.setName = setName.methodize();
 // Use the method instead
obj.setName('Barney');
obj.name;
// -> "Barney"

The example above is quite simplistic. It's more useful to copy methodized functions to object prototypes so that new methods are immediately shared among instances. In the Prototype library, methodize is used in various places such as the DOM module, so that (for instance) you can hide an element either by calling the static version of Element.hide and passing in an element reference or ID, like so:

Element.hide('myElement');

...or if you already have an element reference, just calling the methodized form instead:

myElement.hide();