Exactly matching keys in object

exact-keys.ts

// #region Ensure CharacterData has the exact same keys as characterProperties
type TypeCheck<T extends true> = T;
// KeyDifference will be `never` when CharacterData's keys exactly match those
// of characterPropertiesMap, otherwise it will include the mismatching keys
type KeyDifference = Exclude<
  keyof typeof characterPropertiesMap | keyof CharacterData,
  keyof typeof characterPropertiesMap & keyof CharacterData
>;
// Typescript will throw a compile error with the mismatching keys (if any)
export type AssertExactKeys = TypeCheck<
  KeyDifference extends never
    ? true
    : {
        error: "Keys don't match exactly";
        missingInCharacterDataType: Exclude<
          keyof typeof characterPropertiesMap,
          keyof CharacterData
        >;
        extraInCharacterDataType: Exclude<
          keyof CharacterData,
          keyof typeof characterPropertiesMap
        >;
      }
>;
// #endregion