输出什么?

const createMember = ({ email, address = {}}) => {
	const validEmail = /.+\@.+\..+/.test(email)
	if (!validEmail) throw new Error("Valid email pls")

	return {
		email,
		address: address ? address : null
	}
}

const member = createMember({ email: "my@email.com" })
console.log(member)

A. { email: "my@email.com", address: null } B. { email: "my@email.com" } C. { email: "my@email.com", address: {} } D.

答案： C

解析：

address 的默认值是一个空对象 {}。当我们设置 member 变量为 createMember 函数返回的对象，我们没有为address参数传值，意味着address的值为默认的空对象 {}。一个空对象是一个truthy值，意味着 address ? address : null 条件会返回 true。address的值为空对象 {}。