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sebinsua/generic-maths-in-ts.ts

Last active September 3, 2022 18:53
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generic-maths-in-ts.ts
type CreateArray<V extends number, Arr extends unknown[] = []> =
Arr extends { length: V } ? Arr: CreateArray<V, [...Arr, 1]>;
type Add<A extends number, B extends number> = [...CreateArray<A>, ...CreateArray<B>]['length'];
type V = Add<2, 3>;
type Sub<A extends number, B extends number> = CreateArray<A> extends [...CreateArray<B>, ...infer Els] ? Els['length'] : never;
type V2 = Sub<10, 1>;
type Mul<A extends number, B extends number, Arr extends unknown[] = []> =
CreateArray<B> extends { length: 0 } ? Arr['length'] : CreateArray<B> extends [1, ...infer Els] ? Mul<A, Els['length'], [...Arr, ...CreateArray<A>]> : never;
type V3 = Mul<3, 7>;
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sebinsua commented Aug 25, 2022 •
edited

Might be fun to do some other operations (Div, Mod etc), and to explain conceptually what is going on. Perhaps also to take a look at whether other people have achieved this in a worse or better way?

See: https://github.com/grantila/meta-types

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