ES6 curly braces usage when extracting from an object and assigning to another object

Question

I would like to use curly braces to replace this code:

let rUsers = children.map((user) => {
    let rUser= {};
    rUser.firstName = user.firstName;
    rUser.lastName = user.lastName;
    rUser.relation = user.patron.relation;
    return rUser;
 });

This is what I have:

let rUsers = children.map((user) => {
    let rUser = {};
    ({
        firstName: rUser.firstName,
        lastName: rUser.lastName,
        patron.relation: rUser.relation, // I get an error here
    } = user);
    return rUser;
}

Except for patron.relation, the rest of the extraction works.

Questions:

1. How should I extract value of user.patron.relation?
2. Is there a more succint way of writing the above?

Thanks!

Answer 1

How should I extract value of user.patron.relation?

You would use { … patron: {relation: rUser.relation}, … } as the destructuring target.

Is there a more succint way of writing the above?

If the property names don't match there's not much you can do, but in your particular case you can simplify by destructuring the parameter into multiple variables:

const rUsers = children.map(({firstName, lastName, patron: {relation}}) => 
    ({firstName, lastName, relation})
);