Mem leak about vue-image-lightbox

[pexea12]

Hammer is not a traditional event emitter from javascript. It is only a normal object which follows observer pattern. Therefore, there is no need to destroy it because Javascript garbage collector will do it for us.

[imcvampire]

No, you still have to stop, destroy and set this variable to null to get garbage collector work.
You can check its documentation (http://hammerjs.github.io/api/) and an example from a react component (https://github.com/JedWatson/react-hammerjs/blob/master/src/Hammer.js#L122)

[pexea12]

You are right in case of a dangling pointer where you attach an event to an outside component.

For example, if you attach event e to component Father which uses component Child. If Child is destroyed but Father and e are alive, then there will be a problem. Therefore, e must be detached and destroyed also. However, if Child and Father are destroyed, there will be no dangling references and garbage collector can work well without killing e.

You should notice that I attach 2 hammer event to a DOM component which is inside the lightbox. After the lightbox is destroyed, both the hammer object and this DOM component are destroyed also. Therefore it is unnecessary to detach and destroy the attached events.

In the React component vue-hammer above, you can see that the hammer object is a property of the component (this.hammer). Hence, when the component is unmounted, he must kill the event because the DOM component is destroyed but hammer is still alive. Things are different in the lightbox because hammer is destroyed even before the DOM component is destroyed. I used to consider detach it but I found it unnecessary.

[imcvampire]

Thank you, I get your point! But I will do more test to make sure everything works properly!