Numbers With Same Consecutive Differences

export function numsSameConsecDiff(n: number, k: number): number[] {
  const answer: number[] = [];
 
  function dfs(current: string) {
    if (current.length === n) {
      answer.push(+current);
      return;
    }
    const prev = +current[current.length - 1];
    for (let i = 0; i < 10; i++) {
      if (Math.abs(prev - i) === k) {
        dfs(current + i);
      }
    }
  }
 
  for (let i = 1; i < 10; i++) {
    dfs(i.toString());
  }
 
  return answer;
}