Question

When I load a page I am calling addEventListener to initialize deviceReady, inside that addEventListener I want to call a function which is inside a class. See the following example:

Example class

var HomePageModel = function(){
    
    this.initModule = function(){
    //doing some process;
    };
};

I want to call the above initModule function in addEventListener.

Like

document.addEventListener("deviceready", HomePageModel.initModule, false);

Is it possible to call class function inside a eventlistener which is outside of a class?

Answer 1

You need an instance first:

document.addEventListener("deviceready", new HomePageModel().initModule, false);

Note that if your initModule method uses this, it won’t work, because this will be set to the element that triggered the event. To avoid that, you can create a new function bound to a fixed value of this:

var model = new HomePageModel();
var boundFn = model.initModule.bind(model);
document.addEventListener("deviceready", boundFn, false);

Finally, you can always use a wrapper function as the event handler, and call your module initializer from there (not sure why you haven’t considered that):

document.addEventListener("deviceready", function(){
    new HomePageModel().initModule();
}, false);