JavaScript

Array.prototype.with()

Promise.allSettled()

flatten a nested array

top level await

object group by

nullish coalescing

structured clone

private class fields

array at method

optional chaining

Total up the instances of items in an array

console.log groups

console.log passed function argument

Convert object to array

dedupe an array

Enforce required parameters

Implicit return object

Object Literal console logs

Template literals