Can I rely on group$.key from groupBy?

[Sawtaytoes]

I need an easy way to access the key from groupBy. From what I saw, I can do group$.key. Dunno if I should be relying on .key being there.

Here's what I have:

groupBy(({
  groupKey,
}) => (
  groupKey
)),
mergeMap((
  group$,
) => (
  group$
  .pipe(
    pluck('data'),
    toArray(),
    map((
      dataArray,
    ) => ({
      dataArray,
      key: (
        group$
        .key
      ),
    })),
  )
)),

Without adding a mergeMap, I have no way of getting the passed-in key after toArray. That's why I thought to use group$.key. Is this how someone would recommend I do it?

[cartant]

Yes, it's an exported type:

rxjs/src/internal/operators/groupBy.ts

Lines 262 to 271 in 8fdc00d

	/**
	* An observable of values that is the emitted by the result of a {@link groupBy} operator,
	* contains a `key` property for the grouping.
	*/
	export interface GroupedObservable<K, T> extends Observable<T> {
	/**
	* The key value for the grouped notifications.
	*/
	readonly key: K;
	}

[Sawtaytoes]

Thanks! That's awesome.

I must've missed it when I was looking the docs yesterday. I see it now though 🤷‍♂️: