严格模式下的对象

Question

I have an object and I need it to run the content of the page. I need to wrap it with strict mode. I tried to return it to use in global scope, but it didn't solve my issue.

(function($) {
   "use strict";

   var MyObj = {
       // some code here.
   }

   return MyObj;

})(jQuery);

console.log(MyObj); // <= undefined

How can I access to this object from anywhere of my project?

Answer 1

What you have there is an immediately-invoked function expression (IIFE) which is specifically designed to keep things separate from the external scope. Since you're returning MyObj , all you have to do to make it available in the global scope is this:

var MyObj = (function($) {
    "use strict";

    var MyObj = {
        // some code here.
    }

    return MyObj;

})(jQuery);

console.log(MyObj);

The other way to do this would be to put MyObj in the global space explicitly. In a browser, the global object is called window , so you could, inside your IIFE, say window.MyObj = { /* some code here */ } . I would discourage this approach, though, because it's not clear to the outside observer that that's happening (ie, you would have to rely on documentation). The better approach is to return the objects you want to expose, and the caller can choose to put those in global space.

Answer 2

Using use strict , you can only put an Object in int the global namespace explicitly. For example, you could use window.myObj = MyObj in your function.

Another possible way to achieve your goal is by passing the global object to your function (it could be window in the browser or global in nodejs).

(function($, global) {
   "use strict";
   var MyObj = {}
   global.myObj = MyObj;
})(jQuery, window);

Moreover, as Ethan suggested, since you return MyObj, you could simply assign the result of the invocation to a variable.

var myObj = (function($) {
   "use strict";
   var MyObj = {}
   return x
})(jQuery);
myObj; //now defined in the global scope