const object = {a: 1, b: 2}
const array  = [3,4]

// Value expression
const foo = {...object, c: 3} // == {a: 1, b: 2, c: 3}
const bar = [...array,  5, 6] // == [3, 4, 5, 6]

// Destructuring assignment
{
  const {a, ...rest} = foo // a == {a: 1}; rest == {b: 2, c: 3}
}
{
  const [b, c, ...rest] = bar // b == 3; c == 4; rest == [5, 6]
}