Function isReadableStore

isReadableStore<T>(store: unknown): store is Readable<T>
Provides a basic test for a given variable to test if it has the shape of a readable store by having a subscribe function.

Note: functions are also objects, so test that the variable might be a function w/ a subscribe function.
Type Parameters
- T
  type of data.
Parameters
- store: unknown
  variable to test that might be a store.
Returns store is Readable<T>
Whether the variable tested has the shape of a store.