Destructuring: defaults

When destructuring you can also provide default values

just assign a default value, like so a=1

const [a:1] = []; assert.equal(a, 1);

for a missing value

const [b=2] = [1,,3]; assert.equal(b, 2);

in an object

const [a, b=2] = {a: 1}; assert.equal(b, 2);

if the value is undefined

const {a, b} = {a: 1, b: void 0}; assert.strictEqual(b, 2);

also a string works with defaults

const [b=2] = '1'; assert.equal(a, '1'); assert.equal(b, 2);