访问JavaScript中对象的枚举成员

Question

I'm trying to pass an "Options"-Object to the constructor of another object. Options have enumerations which I try to read in another file.

js/mainApp.js:

square = new World(20, 20, null, 0);

var opts = new Options(MODE.SINGLE, REGION.MIDDLE_EAST);
world = new World(0, 0, "img/whatever.png", opts);

js/options.js :

var MODE = {
    SINGLE : 1,
    MULTI  : 2
};

var REGION = {
    MIDDLE_EAST : { xTranslate : -2300, yTranslate: -700, scale : 1.2}
};

function Options(MODE, REGION) {
    this.mode = MODE;
    this.region = REGION;
}

Now in the World constructor I'm getting the error " opts.region is undefined " for the second alert. For some reason the first alert shows the expected " { xTranslate : -2300, yTranslate: -700, scale : 1.2} "

js/options.js:

var World = ExtendingSomething.extend(
{
    initialize: function(x, y, imageURL, opts) {
        alert (JSON.stringify(opts.region));
        alert (JSON.stringify(opts.region.scale));
        ...
    }
}
);

Edit: I added few information

I don't understand why I'm getting this error is undefined while it works in in this jsfiddle (thanks for creating to Thomas CG de Vilhena).

Maybe it's a problem that I'm using different files? still: Why is there no problem with the call opts.region , but as soon as I'm calling opts.region.scale the error opts.region is undefined appears(not opts.region.scale!).

<script type="text/javascript" src="js/mainApp.js"></script>
<script type="text/javascript" src="js/options.js"></script>
<script type="text/javascript" src="js/world.js"></script>

Edit: I needed to add another line of code to understand the problem

Answer 1

The problem is the constructor call with wrong parameters. There should be some kind of type check, otherwise it gives a TypeError.

remove any wrong call to constructor or add a check

square = new World(20, 20, null, 0);

Answer 2

Script files should be loaded in below order.

<script type="text/javascript" src="js/options.js"></script>
<script type="text/javascript" src="js/world.js"></script>
<script type="text/javascript" src="js/mainApp.js"></script>

It seems we are using objects even before they are being loaded.