Undefined Test Not Working In Javascript

I'm getting the error 'foo' is undefined. in my script when i test my function with an undefined parameter. As far as I understand, This shouldn't be happening. My calling code: //

Solution 1:

You can't pass a variable that doesn't exist (undefined, not null...which does exist) into a function, it's trying to get the value of foo to pass it when you call

var test = peachUI().stringIsNullOrEmpty(foo);

...and it isn't there, so you're getting the error on just that line, just as you would with a simpler case:

alert(foo);

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Now if you tried to call it as a property of something, then it'd be valid, for example:

alert(window.foo);

Then undefined gets passed in, because it's an undefined property on a known/present object.

Solution 2:

I get the error too, but it is is not related to your code, it is because you pass a variable that does not exist to a function. This works:

var foo = undefined;
var test = peachUI().stringIsNullOrEmpty(foo) ;

Btw. the error already tells you that the problem is not in your function, otherwise it be 'testString' is undefined.