Pass enum as generic to type?-CodePudding

I have enum:

enum A {
  a = 'a',
  b = 'b',
}

And a type:

type B<T = A> = {
   values: Record<T, string>; // error Type 'T' does not satisfy 
           //              the constraint 'string | number | symbol'.   

   // Type 'T' is not assignable to type 'symbol'.
}

Then I want to use it const someVar: B<someEnum>;.

Question: am I able to somehow pass enum as a generic to a type?

CodePudding user response：

Yes, if you're ok with something like this:

type B<T extends A = A> = {
   values: Record<T, string>;
}

You won't be able to generalize enum though. Quoting the docs:

In addition to generic interfaces, we can also create generic classes. Note that it is not possible to create generic enums and namespaces.

CodePudding user response：

If you want to use the Enum keys of A, you need to extract them from the type it self.

Here is a sample on how you can achieve that:

enum A {
  a = 'a',
  b = 'b',
}

type B<T extends string = keyof typeof A> = {
   values: Record<T, string>;
  }

const object1 : B = {
values: {
  "a": "123",
  "b": "123"
}  
}