es6-object-assign.js

const objA = {
    a: 1,
    b: 2
}

const objB = {
    ... objA
    b: 3,
    c: 4
}

// Is equivalent to:
const objB = Object.assign({}, objA, { b: 3, c: 4 });

console.log(objA, objB);
// { a: 1, b: 2 } { a: 1, b: 3, c: 4 }