js 拿到下一个序列化整数

function getNextInt(int) {
  const config = int.reverse().reduce(
    (config, digit) => {
      let sum = digit + config.increment,
        nextInt = config.nextInt,
        increment = 0;

      if (sum > 9) {
        nextInt.push(sum - 10);
        increment = 1;
      } else {
        nextInt.push(sum);
      }

      return {
        increment,
        nextInt,
      };
    },
    { increment: 1, nextInt: [] }
  );

  if (config.increment) {
    config.nextInt.push(1);
  }

  return config.nextInt.reverse();
}

console.log(getNextInt([9, 9, 9])); // [1, 0, 0, 0]
console.log(getNextInt([9, 9, 9, 0])); // [9, 9, 9, 1]
console.log(getNextInt([9, 9, 9, 0, 1])); // [9, 9, 9, 0, 2]
console.log(getNextInt([9, 9, 9, 0, 9])); // [9, 9, 9, 1, 0]