如何用前导零填充负整数？

function padWithZeros(num, width) {
  let str = Math.abs(num).toString();
  while (str.length < width) {
    str = '0' + str;
  }
  return num < 0 ? '-' + str : str;
}

console.log(padWithZeros(-123, 5)); // 输出: -00123

function padWithZeros(num, width) {
  let str = Math.abs(num).toString();
  return `${num < 0 ? '-' : ''}${'0'.repeat(width - str.length)}${str}`;
}

console.log(padWithZeros(-123, 5)); // 输出: -00123

const _ = require('lodash');

function padWithZeros(num, width) {
  let str = _.padStart(Math.abs(num).toString(), width, '0');
  return num < 0 ? '-' + str : str;
}

console.log(padWithZeros(-123, 5)); // 输出: -00123