JavaScript: Remove a property from an object immutably by destructuring it

Say you have a JavaScript object like this:

const user = {
    firstName: 'Bramus',
    lastName: 'Van Damme',
    twitter: 'bramus',
    city: 'Vinkt',
    email: '[email protected]',
};

And now say you want to create a copy of the whole object, containing all properties except for the email property.

# The oldskool way:

The first idea that came to my mind was to clone/copy the object and then successively remove email from the new object using the delete operator:

const userWithoutEmail = Object.assign({}, user);
delete userWithoutEmail.email;

But that could use some more ES2015 syntax, no?

# Remove an Object property using Destructuring + Rest Properties:

Thanks to Destructuring and Object Rest/Spread Properties (currently stage 3), we can also do this:

const {
    email,
    ...userWithoutEmail
} = user;

This little piece of code lifts email from the user object (e.g. destructuring), and then collects all remaining properties into userWithoutEmail (e.g. rest spreading). Handy!

# Remove a variable object property using Destructuring + Rest Properties:

If you want to remove a certain property through a variable containing its name, use this syntax:

const propertyToRemove = 'email';

const {
    [propertyToRemove]: removed,
    ...userWithoutEmail
} = user;

Since you’re using a dynamic field, you need to use [] to destructure the property from the object. Its result is then aliased into a variable named removed. What’s left is over, is collected into userWithoutEmail