Destructuring assignments can have default values.

const [one, two, three = "tres"] = ["uno", "dos"]
console.log(three) // "tres"

const { uno, dos = "two", tres } = { uno: "one", tres: "three" }
console.log(dos) // "two"

The same goes for function parameters.

function foo({ uno, dos = "two", tres }) {
  console.log(dos) // "two"
}

foo({ uno: "one", tres: "three" })

See Also⌗