TypeScript 复用型 generics

Question

How to extend generic type generics of type to function? Is it possible to reuse generics without copy paste?

type T<FormType extends 'edit' | 'create' = 'create', RecordType extends Record = Record> = {
   type: FormType,
   record: RecordType
}

const func = <FormType extends 'edit' | 'create' = 'create', RecordType extends Record = Record>(props: T<FormType, RecordType>) => ...

How to extend this <FormType extends 'edit' | 'create' = 'create', RecordType extends Record = Record> <FormType extends 'edit' | 'create' = 'create', RecordType extends Record = Record> from type generics to function generics without copy paste?

Answer 1

Something you could do is break it down to one Base type:

type GenericType = {
  formType: 'edit' | 'create'
  recordType: Record
}

type Base = {
  formType: 'edit';
  recordType: Record
}

type T<B extends GenericType = Base> = {
   type: FormType,
   record: RecordType
}

const func = <B extends GenericType = Base>(props: T<B['formType'], B['record']>) => ...

I find this helps with verbosity a lot especially as I add a lot of generics in.