Question

I am trying to get some variables into a script I am loading. Currently, I have like

window.myApp = {
    id: ''
};

And I am loading the javascript like

(function() {
    var s = document.createElement('script');
    s.type = 'text/javascript';
    s.async = true;
    s.src = 'http://blah.com/widget.js';
    var x = document.getElementsByTagName('script')[0];
    x.parentNode.insertBefore(s, x);
  })();

widget.js has the namespace window.myApp and I am trying to get the .id into it ? How can I do that?

Answer 1

Within widget.js you could do this:

var alreadyDefinedProps = window.myApp;

window.myApp = {
   // whatever properties widget.js has currently
}

if (alreadyDefinedProps) {
   for (var prop in alreadyDefinedProps)
       window.myApp[prop] = alreadyDefinedProps[prop];
}

That is, store a reference to the existing window.myApp object, then set window.myApp to another object, then copy the properties across. You could add an if test to handle the case where the same property is defined in both JS files.