判断是否是回文数

function isPalindromic(target) {

  target = String(target)

  let length = target.length - 1

  for (let i = 0; i < target.length; i++)

    if((target[i] != target[length--])) return false

  return true

}

function isPalindromic(target) {

  const hash = {}

  target.__proto__.replace = ''.replace

  target.replace(/\d/ig, (item, i,c) => {hash[i] = +item, hash['length'] = i + 1})

  const values = Object.values(hash)

  return values.every((_, i) => hash[i] === values[--hash['length']])

}

const isPalindromic = target => String(target).split('').reverse().reduce((current, item) => current + item) == target

const isPalindromic = target => Number(String(target).split('').reverse().join('')) == target

function isPalindromic(target) {

  let stack = []

  while (target > 0) {

    stack.push(target % 10)

    target = ~~(target / 10)

  }

  let length = stack.length

  for (let i = 0; i < stack.length; i++)

    if(stack[i] != stack[--length]) return false

  return true

}

console.log(isPalindromic(12321)) // true

console.log(isPalindromic('123321')) // true

console.log(isPalindromic(123)) // false