How to assert a spy is invoked with event on click using jasmine?

Question

I\'m writing a simple click handler and need the event passed in (like so)

Thing = function($){

    var MyObject = function(opts){
        this.opts = opts;         


        

Answer 1

You have to trigger your own event passing a spy for the stopPropagation method, cause you wanna test if the event was stopped.

var event = {
    type: 'click',
    stopPropagation: function(){}
}
var spy = spyOn(event, 'stopPropagation');
$('#some_dom_element').trigger(event);
expect(spy).toHaveBeenCalled();

Note: there is code smell when you spy on the object you want to test, because you start to test the inner behavior of your class. Think about your function as a black box and test only the things you put in and get out. In your case, renaming the function in will break the test, while the code is still valid.

Answer 2

If you can't use jQuery you may use dispatchEvent and check its return value (based on this answer).

const domElem = document.getElementById('some_dom_element');
const clickEvent = new MouseEvent('click', {
  view: window,
  bubbles: true,
  cancelable: true
});

const cancelled = !domElem.dispatchEvent(clickEvent);
expect(cancelled).toBeTruthy();