Recursive conditional types

Question

I\'d like to map an object recursively so that the primitive values in the object are converted to some other type.

For example, I\'d like an object like this:

Answer 1

You were really close. The problem here is that string is assignable to {}.

Demonstration of this fact here.

If you check for the string, number, etc. first before {}, then you can get what you want:

type ConvertToTest = {
    [P in keyof T]: T[P] extends any[]
        ? ConvertToTest
        : T[P] extends string
        ? Test
        : T[P] extends number
        ? Test
        : T[P] extends boolean
        ? Test
        : ConvertToTest
}