I'm currently using CamelCasedPropertiesDeep type and I found that it's not copy Date type, instead it creates copy of it. I've got this error

Argument of type '{ toString: () => string; toDateString
string; toLocaleString: { (): string; (locales?: string | string[] | undefined, options?: DateTimeFormatOptions | undefineON: (key?: any) => string; }' is not assignable to parameter of type 'number | Date'.

So I tried it with another standard build-in object types and it works with none of them.

interface ExampleType {
    bool: Boolean
    sym: Symbol
    error: Error
    num: Number
    bigInt: BigInt
    math: Math
    date: Date
    str: String
    regExp: RegExp
    array: Int8Array
    map: Map<any,any>
    weakMap: WeakMap<any, any>
    weakSet: WeakSet<any>
    json: JSON
    promise: Promise<any>
    generator: Generator
    dateTimeFormat: Intl.DateTimeFormat
}

type CamelizedExample = CamelCasedPropertiesDeep<ExampleType>

Here you can try to camelize keys of an object I've present above and notice this issue.