Non-Empty type util for typescript

NonEmptyUtil.ts

declare const nonEmpty: unique symbol;

type NonEmpty<T> =
  T extends string ? T & `${string & {}}${string}` :
  T extends readonly unknown[] ? T & { readonly 0: T[0] } :
  T extends object ? T & ({} extends T ? { [nonEmpty]: never } : {}) :
  never;

const arr: NonEmpty<string[]> = ['foo'];
const obj: NonEmpty<{ x: number }> = { x: 1 };
const str: NonEmpty<'hello'> = 'hello';

// Errors:
const emptyArr: NonEmpty<string[]> = [];
const emptyStr: NonEmpty<string> = '';
const emptyObj: NonEmpty<object> = {};