spread-operator.js

const first = {
  foo: 1,
  bar: 1
}

// Copy the first object into a new one and override the bar property. This is useful when you
// want to make a copy of a complex object and want to override just one particular part of it.
const second = {
  ...first,
  bar: 2
}

console.log(first)
/*
  Output is...
  
 {
   foo: 1,
   bar: 1
 }
 
*/

console.log(second)

/*
  Output is...
  
 {
   foo: 1,
   bar: 2
 }
 
*/