Null coalescing operator for JavaScript

Very often in javascript some function parameters are optional. So, code like this become needed:

 

if (typeof something == "undefined")

    alert("something is undefined");

 

However, there is a better, slicker solution. This is a null coalescing operator in javascript "terms":

 

function DoSomething(element)

{

    element = element || document.body;

}

 

function DoSomething(index)

{

    index = index || 0;

}

 

 

In example above element variable gets value of document.body if null (undefined). Similarly index variable gets 0 value if undefined or null.


Posted on Sunday, December 12, 2010 by | Add Comment

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