import type { Args, Fn } from "../HKT";
import type { AssertStr } from "../helpers";

/**
 * Prepend a string (the 1st argument) to another string (the 2nd argument).
 *
 * Sig: `(prefix: string, s: string) => string`
 */
export type Prepend<Prefix extends string, S extends string> = AssertStr<`${Prefix}${S}`>;

/**
 * [Fn] Prepend a string (the 1st argument) to another string (the 2nd argument).
 *
 * Sig: `(prefix: string, s: string) => string`
 */
export default interface PrependFn extends Fn<[string, string], string> {
  def: ([prefix, s]: Args<this>) => Prepend<typeof prefix, typeof s>;
}