Did anyone succeed in writing a type for UUID in Typescript using the new template literal types?
E.g.:
const id:UUID = "f172b0f1-ea0a-4116-a12c-fc339cb451b6"
This guy here tried: UUID Tweet
But the type was too complex: "Expression produces a union type that is too complex to represent.(2590)": Example
His type:
type Numeric = '0' | '1' | '2' | '3' | '4' | '5' | '6' | '7' | '8' | '9'
type Alphabetic = 'a' | 'b' | 'c' | 'd' | 'e' | 'f' | 'g' | 'h' | 'i' | 'j' | 'k' | 'l' | 'm' | 'n' | 'o' | 'p' | 'q' | 'r' | 's' | 't' | 'u' | 'v' | 'w' | 'x' | 'y' | 'z'
type Alphanumeric = Alphabetic | Numeric
type Repeat<
Char extends string,
Count extends number,
Joined extends string = ``,
Acc extends 0[] = []
> = Acc['length'] extends Count ? Joined : Repeat<Char, Count, `${Joined}${Char}`, [0,...Acc]>
type UUIDV4 = `${Repeat<Alphanumeric, 8>}-${Repeat<Alphanumeric, 4>}-${Repeat<Alphanumeric, 4>}-${Repeat<Alphanumeric, 4>}-${Repeat<Alphanumeric, 12>}`
Yuriy Bogomolov posted a solution for this on his blog: https://ybogomolov.me/type-level-uuid.
Here's his solution (cf. TypeScript Playground):
type VersionChar =
| '1' | '2' | '3' | '4' | '5';
type Char =
| '0' | '1' | '2' | '3'
| '4' | '5' | '6' | '7'
| '8' | '9' | 'a' | 'b'
| 'c' | 'd' | 'e' | 'f';
type Prev<X extends number> =
[never, 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, ...never[]][X];
type HasLength<S extends string, Len extends number> = [Len] extends [0]
? (S extends '' ? true : never)
: (S extends `${infer C}${infer Rest}`
? (Lowercase<C> extends Char ? HasLength<Rest, Prev<Len>> : never)
: never);
type Char4<S extends string> = true extends HasLength<S, 4> ? S : never;
type Char8<S extends string> = true extends HasLength<S, 8> ? S : never;
type Char12<S extends string> = true extends HasLength<S, 12> ? S : never;
type VersionGroup<S extends string> = S extends `${infer Version}${infer Rest}`
? (Version extends VersionChar
? (true extends HasLength<Rest, 3> ? S : never)
: never)
: never;
type NilUUID = '00000000-0000-0000-0000-000000000000';
type UUID<S extends string> = S extends NilUUID
? S
: (S extends `${infer S8}-${infer S4_1}-${infer S4_2}-${infer S4_3}-${infer S12}`
? (S8 extends Char8<S8>
? (S4_1 extends Char4<S4_1>
? (S4_2 extends VersionGroup<S4_2>
? (S4_3 extends Char4<S4_3>
? (S12 extends Char12<S12>
? S
: never)
: never)
: never)
: never)
: never)
: never);
const getUser = <S extends string>(id: UUID<S>): void => console.log(id);
getUser('00000000-0000-0000-0000-000000000000'); // ✅ special Nil UUID
getUser('11111111-1111-0111-1111-111111111111'); // ✅ error: version 0 is a special case
getUser('11111111-1111-1111-1111-111111111111'); // ✅ version 1
getUser('11111111-1111-2111-1111-111111111111'); // ✅ version 2
getUser('11111111-1111-3111-1111-111111111111'); // ✅ version 3
getUser('11111111-1111-4111-1111-111111111111'); // ✅ version 4
getUser('11111111-1111-5111-1111-111111111111'); // ✅ version 5
getUser('11111111-1111-6111-1111-111111111111'); // ✅ error: version 6 doesn't exist
getUser('11111111-1111-1111-1111-11111111111'); // ✅ error: invalid format