new操作符

function newFactory(constructor, ...args) {
  if (typeof constructor !== 'function') {
    throw new Error('constructor must be a function')
  }

  const object = Object.create(constructor.prototype)
  const result = constructor.apply(object, args)

  if (result && (typeof result === 'object' || typeof result === 'function')) {
    return result
  } else {
    return object
  }
}