@ly-js/ui/es/utils/types.d.ts

`@ly-js/ui` 是基于`vue3`常用库，会在`@ly-js/element`、`@ly-js/vant`中引入

export declare type Nullable<T> = T | null;
export declare type Mutable<T> = {
    -readonly [P in keyof T]: T[P];
};