I don't understand the use of the spread operator with mongoose

Question

I don't understand the use of the spread operator in the following code:

exports.create = (req, res, next) => {
    const itemObject = JSON.parse(req.body.item);
    const item = new Item({
        ...itemObject,
        name: 'test' 
    });
};

I tried to write itemObject instead of ...itemObject but it doesn't work. Why do you have to create a copy of the object with spread operator for this to work?

Thanks for your help

Answer 1

Because if you don't spread it you're creating an "itemObject" property and value. You're effectively doing this:

const item = new Item({
  itemObject: itemObject,
  name: 'test'
});