Java Reference
In-Depth Information
Borrowing Methods from Prototypes
It is possible to borrow methods from objects without having to inherit all their properties
and methods. This is done by making a reference to the function that you want to borrow
(that is, without parentheses so that it isn't invoked).
For example, the batman object does not have any of the super-power methods that the
superman object has, but we can create a reference to them that can then be used by an-
other object. For example, we can create a fly() function by referencing the superman
object's fly method:
fly =;
<< function () {
return "Up, up and away! " + + " soars
through the
This method can now be called on another object using the call method that all functions
<< "Up, up and away! Batman soars through the air!"
Borrowing Array Methods
One of the most common uses of borrowing methods is from arrays. There are many array-
like objects in JavaScript, such as the arguments object that's available in functions and
the node lists that many of the DOM methods return. These act like arrays but are missing a
lot of the methods arrays have—often it would be convenient if they had them.
For example, the arguments object can use the slice method from the Array con-
structor's prototype by assigning a variable that points to it:
slice = Array.prototype.slice;
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