CODEWITHSUNDEEP
javascript
Daryl
Daryl

Reputation: 18895

How to Reference Defined Values

I have a javascript file that is attempting to reference a previously defined value, but the container of the value is null:

if (typeof (myNamespace) == "undefined") { myNamespace = {}; }

myNamespace.myClass = {
    myConstants: {
        value: "someValue",
    },

    something : {
        values: [myNamespace.myClass.myConstants.value] // Errors here
    }
};

I thought JavaScript executed in a top down manner, so the myNamespace.myClass.myConstants.value should be already be defined when the something.values[] is getting populated.

Upvotes: 1

Views: 18

Answers (1)

Pointy
Pointy

Reputation: 413737

At the point your expression myNamespace.myClass.myConstants.value is evaluated, the value of myNamespace.myClass is still undefined. Until the whole object initializer expression is evaluated, the assignment doesn't happen.

The upshot of this is that there's no way to make internal cross-references from inside an object initializer expression. You have to split it out into a separate assignment.

myNamespace.myClass = {
    myConstants: {
        value: "someValue",
    },

    something : {
        values: []
    }
};

myNamespace.myClass.something.values.push(myNamespace.myClass.myConstants.value);

Upvotes: 3

Related Questions