JAVASCRIPT

Object.assign()

const obj1 = {
				a: 5,
                b: 2
                }
const obj2 = Object.assign({a:6 d:7}, obj1);

console.log(obj2);
// output:  { a: 5 , b: 2, d:7} 

object.assign in node.js

const newId= tours[tours.length-1].id+1;
const newTour= Object.assign({id:newId},req.body) //object.assign() is used to merge two objects.