Destructure key-value pairs

Set up associative array.

const myHash = {
  foo: 1,
  bar: 2,
  baz: 3,
  fizzer: 4
}

Then destructure it.

const {foo, bar, baz, fuzz} = myHash;

> foo
1
> fuzz
undefined

And fizzer was not used.

Destructure an array

const myArray = [1, 2, 3, 4]

Unpack with spread operator and variable.

> [f, b, ...c] = myArray
[ 1, 2, 3, 4 ]
> c
[ 3, 4 ]

Unpack with spread operator and underscore (for REPL).

> [f, b, ..._] = myArray
[ 1, 2, 3, 4 ]
> _
[ 3, 4 ]

Unpack with underscore for REPL use - gives warning.

> [f, b, _] = myArray
Expression assignment to _ now disabled.
[ 1, 2, 3, 4 ]
> f
1
> b
2
> _
3