group- and export last

[jimmywarting]

I help convert a lot of CJS project to ESM
And two rules that help make this migration way easier is if they have a single groped export at the bottom of the file:

// A single exports assignment -> ok
module.exports = {
  first,
  second,
}

// Multiple exports assignments -> not ok!
module.exports.first = true
module.exports.second = true

...then it's just a matter of changing one line:

- module.exports = {
+ export = {
  first,
  second,
}

this makes it way easier to refactor into a ESM and it's more likely that others accepts one such PR, cuz they are also way easier to review and accept.

i think it's also easier to see / control what is being exported when everything is scattered around in the hole file from top to bottom.

Another reason for having exports at the bottom is b/c of this anti- pattern that makes it hard to refactor old prototype based classes to es classes
cuz those functions / variables are hosted to the top.

var { inherit } = require('util')
var { Shape } = require('./Shape.js')
module.exports = Circle

function Circle (radius) {
  this.radius = radius
}

inherit(Circle, Shape)

then when you go ahead and convert this to es classes then you can no longer do: module.exports = Circle at the top of the file

i see this pattern quite a bit from time to time. some think it's easer to declare what is being exported at the top of the file. but it's problematic. change Circle to a class or const/let and the Circle becomes undeclared.

this is why it would also help if exports where at the bottom instead.

There are two rules that helps with this:

https://github.com/import-js/eslint-plugin-import/blob/main/docs/rules/group-exports.md
https://github.com/import-js/eslint-plugin-import/blob/main/docs/rules/exports-last.md

which i think should be added.