rescursively lowercase an object values

rescursive-lowercase.js

function recursiveLowerCase(object) {
  if (Array.isArray(object)) {
    return object.map((value) => recursiveLowerCase(value))
  }
  if (object !== null && object.constructor === Object) {
    return Object.keys(object).reduce((result, key) => (
      Object.assign(Object.assign({}, result), {
        [key]: recursiveLowerCase(object[key].toLowerCase())
      })
    ), {})
  }
  return object
}