ngOnDestroy is not triggered

Steps to reproduce and a minimal demo of the problem demo http://plnkr.co/edit/7uoVecfa62i8No8GtQHI?p=preview Angular2 beta 16 or higher - When I hide first section with nested components using *ngIf, ngOnDestroy of every nested component is triggered - this is OK.

  <div *ngIf="!ff2">
    <my-component
    ></my-component>
    <my-component
    ></my-component>
    <my-component
    ></my-component>
    <my-component
    ></my-component>
    <my-component
    ></my-component>
  </div>

Outpu in console is

    init
    init
    init
    init
    init
    destroy
    destroy
    destroy
    destroy
    destroy

But when I hide second section where subcomponents are duplicated by *ngFor, not every ngOnDestroy is triggered.

<div *ngIf="!ff">
   <my-component
     *ngFor="#i of [1,2,3,4,5,6]"
   ></my-component>
</div>

output in console is

(6) init
(3) destroy

Current behavior not every ngOnDestroy is triggered

Expected/desired behavior every ngOnDestroy should be triggered

Other information in angular2 beta 9 it was working correctly http://plnkr.co/edit/Q8tLJKlpF6wEVcMWfxH1?p=preview

[adammartin1981]

Think I’ve found the issue, it was to do with iterating over a moving target (a decreasing array).

Inside core/src/linker/view.ts, there is a piece of code at line 203:

var children = this.contentChildren;
for (var i = 0; i < children.length; i++) {
   children[i]._destroyRecurse();
}
children = this.viewChildren;
for (var i = 0; i < children.length; i++) {
   children[i]._destroyRecurse();
}

Where children always decreased, but i remained a constant, you could never hit the even items in the array, as i would be ‘1’ on the second loop, but the [1]th item in the array would now be the 3rd item (as the original [0]th item in the array would have been removed and the new [0]th item in the array would now be the 2nd).

A quick fix would be to have:

var children = this.contentChildren;
var i = children.length;

while( i > 0 ) {
   children[i - 1]._destroyRecurse();
   i--;
}

I might knock up a PR at some point, but I didn’t know what anyone else thought?

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