使用默认参数解析falsey和null

Question

I'm trying to understand how falsey and null values are destructured with default parameters. Here are some examples I've ran:

// #1
const person = { email: 'a@example.com' }
const { email = '' } = person
// email is 'a@example.com'

// #2
const person = { email: '' }
const { email = '' } = person
// email is ''

// #3
const person = { email: false }
const { email = '' } = person
// email is boolean false.  why?!

// #4
const person = { email: null }
const { email = '' } = person
// email is null.  why?!

Is there a shortcut I could write to destructure falsey and null values for #3 and #4 so that my email is an empty string?

Answer 1

Only undefined will cause the default initialiser to run. If you want to fall back to your default for all falsy values, use the good old || operator:

const email = person.email || '';