First of all, let me make it clear that what I'm looking isn't a union type but a straight up concatenation i.e Hel + lo = Hello but for string literal types

Essentially I have a function which takes two string literals, a namespace and a name, and combines these with a / in between as it's output, but I can't figure out a way to make the output a string literal and not a generic string.

I need it to be a string literal because the output will be used as a key of an object.

I've tried type intersections(&), +, .concat()

function makeKey<NS extends string, N extends string>(namespace: NS, name: N) {

    return namespace + '/' + name; // <- want this to be `NS + / + N` = `NS/N`

}

// I want this to return a string literal rather than a generic string



const objKey = makeKey('admin', 'home')

// I want typeof objKey to be a string literal: `admin/home`, not a generic `string`

typeof objKey is a generic string but I want it to be a string literal admin/home