ObservedValueUnionFromArray

Extracts a union of element types from an ObservableInput<any>[]. If you have O extends ObservableInput<any>[] and you pass in Observable<string>[] or Promise<string>[] you would get back a type of string. If you pass in [Observable<string>, Observable<number>] you would get back a type of string | number.

type ObservedValueUnionFromArray<X> = X extends Array<ObservableInput<infer T>> ? T : never;