Question

I have my javascript file:

foo.js

var FooNS = {
   T:5,
   S: FooNS.T+5, //ERROR1
   doSomething : function(adder)
   {
     //Do Something here.
   }
};

This is my other js file:

useFoo.js

$(document).ready(function()
{
    FooNS.doSomething(5); //ERROR2
});

These are the two Javascript errors (via Chrome Inspector), that I get on my page which includes the js(s):

• ERROR1 -> Uncaught TypeError: Cannot read property ‘T’ of undefined (foo.js)
• ERROR2 -> Uncaught TypeError: Cannot call method ‘doSomething’ of undefined (in useFoo.js)

I am not able to figure out the reason for these errors/ the correct usage of namespaces. Any suggestions?

Answer 1

T doesn’t exist as a global variable, which is how you are trying to use it.

var FooNS = {
   T:5,
   S: T+5, // <-- here you are trying to access the global variable T
   doSomething : function(adder)
   {
     //Do Something here.
   }
};

What you are looking for is probably something akin to this:

var FooNS = {
   T:5,
   doSomething : function(adder)
   {
     //Do Something here.
   }
};

FooNS.S = FooNS.T+5;

The second error is because FooNS is never created as an object due to the first error, thus FooNS is undefined.