Question

(Specifically, I’m using Backbone Model events)

Can someone help me understand how javascript events work? The following is not working the way I expected and it’s left me confused:

In backbone, I make a change to my model, and immediately afterwards I run some code:

var myVar;
myModel.set('someAttr', true);  // Change my model
myVar = executeSomeFunc();  // Now run some code

Then somewhere else in my codebase I listen for the event and handle it (in my case I am wrapping this model with a collection):

myCollection.on('change:someAttr', changeHandler);  // Listen for the event

What I’m finding is that myVar = executeSomeFunc() is not executing until all the event handlers on the change:someAttr event are done firing. (I’ve checked by attaching a time consuming event handler onto the event)

Is this expected behavior?

Answer 1

Yes. JavaScript is not multithreaded. When you trigger events, all event handlers are immediately executed.