Disclosure
Most of the problems under my TypeHero Challenges folder were either obtained from typehero.dev or from type-challenges repo. Purpose of these articles are just to document my approaches for my easy reference. Please visit the respective links for more info.
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Problem Description
Compute the length of a string literal, which behaves like String#length.
Solutions
Approach
type StringToCharArray<
S extends string,
Res extends number[] = [],
> = S extends `${string}${infer Rest}` ? StringToCharArray<Rest, [...Res, 1]> : Res;
type LengthOfString<S extends string> = StringToCharArray<S>["length"];