Javascript Object is an unordered collection of key and value pairs, these key and value pairs are called a property. The key can be a string and the value of the property can be any value.

There could be an instance where you only want to pass a key to an object only when it has a value so as not to encounter an error for instance when interacting with an api.

Scenario: You have an api that expects a payload of:

{
  name: "Micheal"
  email: "micheal@micheal.co"
  phone: "+23400000000"
  blog_site: "https://michellead.hasnode.dev"
}

for some reason, if your blog_site value is null and you want to omit it, here is a way to go about it:

const personDetails = {
  name: "Micheal",
  email: "micheal@micheal.co",
  phone: "+23400000000",
  blog_site: null
}

const payload = {
  name: personDetails.name,
  email: personDetails.email,
  phone: personDetails.phone,
  ...(personDetails.blog_site && {
    blog_site: personDetails.blog_site
  })
 };

console.log(payload) //{ name: 'Micheal', email: 'micheal@micheal.co', phone: '+23400000000' }

The above checks if the personDetails.blog_site key has a value which is null or undefined and removes it from the payload.

I hope with this, you can see how the conditionally pass a key and value pair to an object. Thanks for reading! 🙂