javascript deep clone

deepClone.js

const isArray = arr => Object.prototype.toString.call(arr) === '[object Array]'
const isObject = obj => Object.prototype.toString.call(obj) === '[object Object]'

/**
 * Deep copy properties from src, and return cloned object
 * @param {Object} src source object to clone from
 */
const deepClone = src => {
  const dest = {}
  const copy = (src, dest) => {
    if (src) {
      Object.keys(src).forEach(key => {
        const value = src[key]
        if (isArray(value)) {
          dest[key] = value.map(item => item)
        } else if (isObject(value)) {
          dest[key] = {}
          copy(src[key], dest[key])
        } else {
          dest[key] = value
        }
      })
    }
  }
  copy(src, dest)
  return dest
}

const a = { a: 12, b: [1, 2, 3, 4, 5], c: { d: { e: [5, 6, 7, 8] } } }
console.log('clone before: ', a)

const b = deepClone(a)

console.log('cloned b: ', b)
b.a = 78
b.c.d.e = []
b.b = [9,8]

console.log('b: ', b)
console.log('a: ', a)