Update index.ts

[KamranAsif]

#1691 PR Checklist

Please check if your PR fulfills the following requirements:

• 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?

[X] Bugfix
[ ] 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?

ActionType is useful for extracting the response type of the new action creators.

Currently, ActionType is only accessible if importing from '@ngrx/store/src/models'.

What is the new behavior?

ActionType can now be imported from @ngrx/store

Does this PR introduce a breaking change?

[ ] Yes
[X] No

Other information

[ngrxbot]

Preview docs changes for dc7061e at https://previews.ngrx.io/pr2081-dc7061e/

[alex-okrushko]

Thanks Kamran!

[SerkanSipahi]

@KamranAsif hi, thank you for your PR! Im interested in an example of:

ActionType is useful for extracting the response type of the new action creators.

Could you show some examples, thank you :)

[KamranAsif]

Hey, sure. It basically allows you to avoid extracting an action's properties to an interface.

before:

class MyAction {
  readonly type = '[Test] my action';
  constructor(readonly foo: number, readonly bar: number) {}
}

function handleAction(action: MyAction) {
  return action.foo + action.bar;
}

With action creators:

const myAction = createAction('[Test] my action', props<{foo: number, bar: number}>);

function handleAction(action: ActionType<typeof myAction>) {
  return action.foo + action.bar
}