Better typescript types

[D-Sketon]

Check List

• I have already read README.
• I have already searched existing issues.
• I have already searched existing pull requrests.

Feature Request

There are still some problems with the current type labeling for warehouses. For example:

warehouse/src/types/virtual.ts

Line 17 in 83df5a1

 get(fn: (this: T) => any): SchemaTypeVirtual<T> { 

Actually, it should be:

get(fn: (this: Document<T>) => any): SchemaTypeVirtual<T> {}

However, it is difficult to refactor the type due to the following implementations:

warehouse/src/document.ts

Lines 19 to 23 in 83df5a1

 constructor(data?: T) { 
   if (data) { 
     Object.assign(this, data); 
   } 
 } 

Additional context

No response

[D-Sketon]

One possible solution is to redefine a new type, e.g:

type DocumentType<T> = Document<T> & T

Then replace Document<T> with DocumentType<T> wherever it needs to be used.
But this could be a big change.