Comments/examples for jschoi to review

README.md

If I understand correctly, this should be similar to Jordan's case

Original code

function putEntries(map, obj) {
  Object.entries(obj).forEach(
    ([k, v]) => map.set(k, v))
}

const map = putEntries(new Map(), {a: 'apple', b: 'banana'})
map.get('a') // 'apple'

3rd party code

delete Map.prototype.set
delete Map.prototype.get
// delete ...

So we need to extract the methods to keep ourself safe

const {get, set} = Map.prototype

function putEntries(map, obj) {
  Object.entries(obj).forEach(
    ([k, v]) => map->set(k, v))
}

const map = putEntries(new Map(), {a: 'apple', b: 'banana'})
map->get('a') // 'apple'

Problem 1

we may need also extract the accessor

const map = putEntries(new Map(), {a: 'apple', b: 'banana'})
map.get('a') // 'apple'
map.size // 2

delete Map.prototype.set
delete Map.prototype.get
delete Map.prototype.size
// ...

but

const {get, set, size} = Map.prototype

doesn't work

You need

const {get, set} = Map.prototype
const size = Object.getOwnPropertyDescriptor(Map.prototype, 'size').get

Too verbose, lose the simplicity of destructuring.

Problem 2

Error-prone if no corresponding accessor syntax, and bind semantic make that even worse

map->size // expect 2, but should be map->size(), so acutally return a bound func

---

Compare: extension proposal

const ::{get, set, size} from Map
// ...
map::size // just work

Highly consistent and simple.

If use -> token, it could be

const ->{get, set, size} from Map
// ...
map->size // just work

I choose :: because I feel -> is more fit for some other usage (for example in pattern match, when PATTERN -> result)

---

About separate namespace

It's an individual issue, but also have a little effect on syntax in this case

const {get, set, size} from Map  // normal namespace
// ...
map->size // just work

This made the const {get, set, size} from Map too close to const {get, set, size} = Map.prototype which would be much error prone.

Even not consider the separate namespace semantic, :: plus from actually is syntax salt which help to make the intention clear and avoid mistakes.