import { type headOfString } from "https://deno.land/x/arktype@v1.0.10-alpha/utils/generics.ts";
definition: S extends `${infer Head}${string}` ? Head : ""
x/arktype/utils/generics.ts>headOfString
import { type headOfString } from "https://deno.land/x/arktype@v1.0.10-alpha/utils/generics.ts";