Destructuring arrays makes shorter code
extract value from array, e.g. extract 0 into x like so let [x] = [0];
let firstValue = [1];
assert.strictEqual(firstValue, 1);
get the last item from array
let lastValue = [1, 2, 3];
assert.strictEqual(lastValue, 3);
swap two variables, in one operation
let [x, y] = ['ax', 'why'];
[x, y] = [x, y];
assert.deepEqual([x, y], ['why', 'ax']);
leading commas
const all = ['ax', 'why', 'zet'];
const [,z] = all;
assert.equal(z, 'zet');
extract from nested arrays
const user = [['Some', 'One'], 23];
const [firstName, surname, age] = user;
const expected = 'Some One = 23 years';
assert.equal(`${firstName} ${surname} = ${age} years`, expected);
chained assignments
let c, d;
let a, b = [c, d] = [1, 2];
assert.deepEqual([a, b, c, d], [1, 2, 1, 2]);
in for-of loop
for (var [a, b] of [[0, 1, 2]]) {}
assert.deepEqual([a, b], [1, 2]);