fix(overmind): typing issues

Author: christianalfoni

packages/node_modules/overmind/src/internalTypes.ts

@@ -18,8 +18,8 @@ export type NestedPartial<T> = T extends Function
 
 export type RehydrateClasses<T extends IState> = Pick<{
   [P in keyof T]: T[P] extends { toJSON: () => infer U } ? (data: U) => T[P] :
-      T[P] extends Array<{ toJSON: () => infer U }> ? (data: U) => T[P][0] :
-      T[P] extends { [key: string]: { toJSON: () => infer U } } ? (data: U) => T[P][0] :
+      T[P] extends Array<{ toJSON: () => infer U }> ? (data: U) => T[P][keyof T[P]] :
+      T[P] extends { [key: string]: { toJSON: () => infer U } } ? (data: U) => T[P][keyof T[P]] :
       T[P] extends IState ? RehydrateClasses<T[P]> :
       never
 },{ [Key in keyof T]: T[Key] extends { toJSON: () => any } | Array<{ toJSON: () => any }> | { [key: string]: { toJSON: () => any } } ? Key : never }[keyof T]>