// deep clone
const deepClone = obj => {
  // check to see if argument is an array/object and assign it to new variable
  const newObj = (Array.isArray(obj)
    ? []
    : {})
  // loop through keys of object OR indexes of array
  // Object.entries() work for arrays!
  for (const [k, v] of Object.entries(obj)) {
    // start deep clone
    newObj[k] = (typeof v === 'object')
      // if value is another array or object, recursively restart the process
      ? deepClone(v)
      // if not, return value
      : v
  }
  return newObj
}