type WebStorageGetMethodReturnType = | Date | RegExp | number | boolean | string | object; type WebStorageGetKeyMethodReturnType = string; export type WebStorageGetItemMethodType = < T extends WebStorageGetMethodReturnType = WebStorageGetMethodReturnType >( key: string ) => T | null; export type WebStorageGetIndexMethodType = < T extends WebStorageGetMethodReturnType = WebStorageGetMethodReturnType >( index: number ) => T | null; export type WebStorageGetKeyMethodType = < T extends WebStorageGetKeyMethodReturnType = WebStorageGetKeyMethodReturnType >( index: number ) => T | null; export type WebStorageGetAllKeysMethodType = () => string[];