Events not removed on toast destroyal leads to memory leak

[waltherjj]

Description

Event listeners for 'toastChanged' and 'remove' are not removed before toast is destroyed, so references to the toast stay in the heap. This leads to serious memory leaks with content-heavy toasts.

Reproduction

Initialize vue-cli-project, add snotify. Make a heap snapshot, perform a garbage collection, open 30 timed out toasts, perform a garbage collection, make second snapshot. Memory usage increases significantly due to not removed listeners.

https://codesandbox.io/s/vue-template-46g5e

We added a footprint property to the toast constructor to make the memory leak more visible.

Solution

Remove event listeners before destroying toast.