combine the array inside object using the spread operator - ecmascript-6

Question

let color = ["blue", "red", "yellow" , "green"]
let dataAdditionalBook= {
Author: "John Doe",
PublishYear: 2020
}
let book = {
Name: "basic programming",
NumberOfPages: 172,
CoverColor:["black"]
}
// the above code should not be changed or deleted at all
/* Write the answer code here */
combine the color variable (combine with the CoverColor attribute) and the dataAdditionalBook into the book variable using the spread operator

Answer 1

As you want to store updated values in book object here you go:
let color = ["blue", "red", "yellow", "green"];
let dataAdditionalBook = {
Author: "John Doe",
PublishYear: 2020,
};
let book = {
Name: "basic programming",
NumberOfPages: 172,
CoverColor: ["black"],
};
book.CoverColor = [...book.CoverColor, ...color];
book = Object.assign(book, dataAdditionalBook);
console.log(book);

Answer 2

first you can combine book CoverColor with with the color
const bookWithNewColor = {...book,CoverColor:[...book.CoverColor,...color]} //updated code here
after that combine bookWithNewcolor and dataAdditionalBook
const newBook = {...bookWithNewColor,...dataAdditionalBook}
console.log(newBook)
the result:
{
name: 'basic programming',
NumberofPages: 172,
CoverColor: [ 'black','blue', 'red', 'yellow', 'green' ],
Author: 'John Doe',
Publish_year: 2020
}