How to create a type that refer to a type of an interface's field?

How to create a type that refer to a type of an interface’s fields?

Here is what I want to achieve:

interface SomeOption {
  readonly name: string;
  readonly value: number;
}

type OptionName = typeof SomeOption.name; // <-- this doesn't work of course

const name: OptionName = 'foo'; // ok
const name: OptionName = 5; // error

I assume that SomeOption might be changed in the future, so I want to say that my variables should be the same type as SomeOption.name, not just string.

But I wonder how to do that.
Thanks

>Solution :

There is another simple syntax:

type OptionName = SomeOption['name'];