ngOnDestroy, ngAfterContentInit and ngAfterViewInit isn't called for site plugins

Download the gapfill question type plugin and install it. Create a quiz with a gapfill question in it. You have an example in here . Edit the file question/type/gapfill/javascript/mobile.js. Inside the componentInit function, right at the start, enter this code: this.ngOnDestroy = function() { alert('Destroyed'); } Clear caches in Moodle (this probably isn't needed, but just in case). In the app, login in that site and go to the quiz. Click to attempt the quiz and check that the gapfill question is rendered. Click back (to leave the quiz). Check that you see an alert with the text "Destroyed".