Platform: Ability to pass in custom memoization function for selectors

[alex-okrushko]

I'm submitting a...

[x] Feature request

What is the current behavior?

Currently the hardcoded memoization is instance equality check, which doesn't work well with arrays.

e.g. I have an array that changes on certain actions and there are many selectors for this data. Some/most selectors return the same items, but because it's a new array all the selector changes are needlessly triggered.

reselect has createSelectorCreator for that purpose.

Expected behavior:

Minimal reproduction of the problem with instructions:

Version of affected browser(s),operating system(s), npm, node and ngrx:

Other information:

[rupeshtiwari]

Hi @brandonroberts ,
Do you want me to work on this enhancement ?

[brandonroberts]

@roopkt I already have a branch in the works for this, but thanks! Could you take a look at https://github.com/ngrx/platform/issues/604? I believe you added the original functionality

[rupeshtiwari]

hi @brandonroberts sure let me take a look thanks.

[alex-okrushko]

Very impressed! Great job!

[rupeshtiwari]

Hi @brandonroberts
I am sorry I was completely absorbed in my office project did not get time to work on it.

[bene-starzengruber]

This is amazing, but it's very hard to find!
It should definitely be included into the NgRx docs with examples:
https://ngrx.io/guide/store/selectors