[알고리즘]reverse a number in JavaScript

const reverse = x => {
const reversedNum = x => parseFloat(x.toString().split('').reverse().join('')) * Math.sign(x);
return reversedNum(x);
}
module.exports = { reverse };

num.toString()

let num = -5432100
num.toString()
// num = '-5432100'

num.split('')

// num = '-5432100'
num.split('')
// num = [ '-', '5', '4', '3', '2', '1', '0', '0' ]

num.reverse()

// num = [ '-', '5', '4', '3', '2', '1', '0', '0' ]
num.reverse()
// num = [ '0', '0', '1', '2', '3', '4', '5', '-' ]

num.join('')

// num = [ '0', '0', '1', '2', '3', '4', '5', '-' ]
num.join('')
// num = '0012345-'

parseFloat(num)

// num = '0012345-'
parseFloat(num)
// num = 12345

num * Math.sign(num)

// original value of num = -5432100
// num = 12345
num * Math.sign(-5432100)
// num = -12345

🐔참고문헌

·freecodecamp web 사이트

https://www.freecodecamp.org/news/js-basics-how-to-reverse-a-number-9aefc20afa8d/