Shorter Implementation of Nominal

[MananTank]

const M = Symbol();

export type Nominal<Name extends string, Type> = Type & {
  readonly [M]: [Name];
};

Works with all the examples mentioned in readme.md

check it out :

https://codesandbox.io/s/nominal-types-l8k9ti?file=/src/nominal.ts

[CryogenicPlanet]

Copying over the response from reddit https://www.reddit.com/r/typescript/comments/w5rebv/comment/ihbgoy3/?utm_source=share&utm_medium=web2x&context=3

We actually have a bug here, will try to patch later tonight

The reason we did the class thing was to try to get this to work

Mins = Nominal<"Mins", number>
Minutes = Nominal<"Mins", number>

const funcMins = (x:Mins) => {}

funcMins(10 as Mins) // works
funcMins(10 as Minutes) // should not work

To be clear, this is not actually working in our code rn. We screwed it up somewhere along the way

But the idea of using the function is NewSymbol is a different Symbol on each function "call" so typescript should ideally see them as different unique symbols. Two unique symbols with the same name will not match. The class is just a mechanism to pass a generic to a function, not doing much else

A basic example of the desired behaviours is here

Actually not super sure how to make an ergonomic way to achieve this off the top of my head, happy to brainstorm

[mochaaP]

We actually have a bug here, will try to patch later tonight

@CryogenicPlanet any progress 😉?

[CryogenicPlanet]

@mochaaP Unfortunately not, don't have a great way in mind to do this without making the UX of the tool much worse. And haven't had the time to spend too much time thinking about it