Angular Change Detection and list references

Question

Does it matter to Angular if in every digest cycle I return a new list with the same contents vs returning the same list instance? This is assuming default change detection, not OnPush.

Answer 1

It will have some impact - ngFor will need to reevaluate each of the elements - it will do identity check. That should be quick, but if you have thousands elements in a big app it may add some overhead, so if you can it's better to return the same list each time.