Suggestion for modifying the use functions

[HIMISOCOOL]

You could change this line and all similar use functions from:

vuex-composition-helpers/src/namespaced.ts

Line 84 in 1af7716

useState: (map?: KnownKeys<TState>[]) => useNamespacedState(store, namespace as string, map),

To be

useState: (...map: KnownKeys<TState>[]) => useNamespacedState(store, namespace as string, map),

which would eliminate the need to explicitly pass the map in as an array:

const { loading, error } = useState('loading', 'error');

[davidmeirlevy]

Interesting idea.

But you suggest it to work for inside the namespaced helper only?

Would you like to contribute this feature? Make sure it must have backwards comparability.

[HIMISOCOOL]

sure, I was thinking for all helpers.

[HIMISOCOOL]

@davidmeirlevy ok so I have a working prototype.

Using useState as an example

export function useState(storeOrMap, map) {
        let store = storeOrMap;

	if (isArray(store)) {
		map = store;
		store = getStoreFromInstance();
	}
	else if (isString(store)) {
		map = Array.from(arguments);
		store = getStoreFromInstance();
	}
	return useMapping(store, null, map, computedState);
}

This works in terms of javascript, however there is an issue with the typescript.
method overloads get messy when you have rest parameters in your signatures

export function useState<TState>(map: KnownKeys<TState>[]): RefTypes<TState>
export function useState<TState>(...keys: KnownKeys<TState>[]): RefTypes<TState>
//                                ^^^^^^^^^^^^^^^^^^^^ `This overload signature is not compatible with its implementation signature.ts(2394)`
export function useState<TState>(store: Store<TState>, map: KnownKeys<TState>[]): RefTypes<TState>
export function useState<TState = any>(storeOrMap: Store<TState> | KnownKeys<TState>[], map?: KnownKeys<TState>[]): RefTypes<TState> {
 ...
}

...keys cant be accurately represented in the implementation signature (the bottom one) so it would never compile...

If the helpers could instead be partially applied (store) => (map) => { ... } or perhaps the useState where you provide store being a different variant it would be doable, but that would be a breaking change.

I have cleaned up some of the code changes I made in the process though and I can make a PR with those changes.

[davidmeirlevy]

Typescript integration is the hardest issue over here, I know.
However, current users depend on it on their codebase, so we must make it work for both cases.

Maybe this function should have several different signatures in order to work. I would go for this type of solution.