feat(component-store): add config for debounce selectors

[alex-okrushko]

PR Checklist

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• The commit message follows our guidelines: https://github.com/ngrx/platform/blob/master/CONTRIBUTING.md#commit
• Tests for the changes have been added (for bug fixes / features)
• Documentation has been added / updated (for bug fixes / features)

PR Type

What kind of change does this PR introduce?

By removing debounceSync from a single-value selector, the selector value now becomes available immediately after the updates.

Longer versions:

• updates/setState were always sync
• selectors now fall into two buckets:
  • state selectors like selector(state => state.foo) are back to being sync
  • selectors that combine other selectors and/or Observables are still async, scheduled to run into the microtask.

Introduce SelectConfig configuration for selector. Currently it allows to "debounce" selector values until the state is "settled".
By default it will be set to debounce: false, as it makes it more predictable (same behaviour as global store) and allows instant reads from the ComponentStore that would return the value synchronously.

Why this change?

While having both types of selectors async/debounced by default is more performant, it was also:

• harder to write test for the ComponentStore(s) (on the user side)
• more confusing for the Developers to understand why the values were not emitted yet,

This last point became more obvious when I saw effects like:

private readonly fooEffect = this.effect<void>(
      obs$ => obs$.pipe(
          withLatestFrom(this.selectedId$),
          switchMap(([, clientId]) => {
            return this.httpApiService.makeACall(clientId);
          }),
          ...

When withLatestFrom is called, the selectedId$ is not ready yet.

The obvious alternative solution would be to provide an imperative way to read the data from the ComponentStore - that solution is also planned and will follow this PR.

[ ] Bugfix
[x] Feature
[ ] Code style update (formatting, local variables)
[ ] Refactoring (no functional changes, no api changes)
[ ] Build related changes
[ ] CI related changes
[ ] Documentation content changes
[ ] Other... Please describe:

What is the current behavior?

Closes #

What is the new behavior?

Does this PR introduce a breaking change?

[x] Yes
[ ] No

ComponentStore selectors are no longer debounced by default.

Other information

[ngrxbot]

Preview docs changes for bb376a5 at https://previews.ngrx.io/pr2606-bb376a53/

[timdeschryver]

I like that the logic of processSelectorArgs is extracted 👍

[alex-okrushko]

Thanks Tim 😊

[timdeschryver]

What if we would extract this ternary statement?
Not sure if it's worth it tho, I'm thinking that when this line changes, the line in the if case would also be changed.

[alex-okrushko]

Yeah, I couldn't think of a better way to extract it and make it readable/somewhat easier to understand at the same time.