Question

define(["dojo/_base/declare"], function (declare) {
    // module:
    //      StyleNames
    // summary:
    //      Style element names.
    var StyleNames = declare(null, 
        {
            PROP1: "Style1",
            PROP2: "Style2"
        }
    );

    StyleNames.dataContexts = [
        StyleNames.PROP1,
        StyleNames.PROP2,
    ];

    return StyleNames;
});

var styleNames = new StyleNames();
console.log("PROP1 is defined as: ", styleNames.PROP1); // prints "Style1"
console.log("dataContexts is undefined: ", styleNames.dataContexts); // Error: styleNames.dataContexts is undefined

My setup was similar to https://stackoverflow.com/a/11329956/1610451 but looking in the DOM, I can see that it is set to the constructor styleNames.constructor.dataContexts with undefined values.

Backstory: I’m porting ActionScript code to JavaScript and need to maintain existing interfaces. An example of the ActionScript code that I’m porting is:

public class StyleNames {
    public static const PROP1 : String = "Style1";
    public static const PROP2 : String = "Style2";

    public static const dataContexts : Array = [
        PROP1,
        PROP2
    ];

    public function StyleNames(){}
}

Answer 1

You’ve got it right in your declaration. That is the most unambiguous way to define static variables in my opinion. In your console.log code, you’re just not referring to the dataContexts variable correctly. It’s a static variable, so it does not belong to any one instance. You want to refer to it this way: StyleNames.dataContexts.

Edit: you’ve also got a possible syntax error in there. Take out the second comma under the StyleNames.dataContexts declaration:

StyleNames.dataContexts = [
    StyleNames.PROP1,
    StyleNames.PROP2
];

Access the variable like this:

StyleNames.dataContexts

as opposed to this.dataContexts or instanceRef.dataContexts