1595810 - [meta] Support globalThis, nullish coalesce operator and conditional chaining operator in ESLint

Status: RESOLVED FIXED

(Developer Infrastructure :: Lint and Formatting, task, P3)

Description

[Julian Descottes [:jdescottes]]

Using globalThis in xpc-shell tests raises an eslint warning. globalThis is supported since FF65, so I guess we could update the rules:
https://searchfox.org/mozilla-central/source/tools/lint/eslint/eslint-plugin-mozilla/lib/configs/xpcshell-test.js
https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/globalThis

Comment 1

[Mark Banner (:standard8)]

I thought I'd already commented on this here, but maybe I was mistaken and it was somewhere else.

The main issue here is that ESLint doesn't know about globalThis when it should do. This is due to a minor issue in the globals module: https://github.com/sindresorhus/globals/issues/140

I've now just submitted https://github.com/sindresorhus/globals/pull/158 which would have helped, however I've just noticed that ESLint has changed their structure of how they do their globals.

I'll wait a couple of days and see what comes out of that pull request, but I might just propose that ESLint adds globalThis directly as it is a stage 4 proposal - ESLint only implements these when they get to stage 4.

Comment 2

[Mark Banner (:standard8)]

At the moment, it seems that globalThis support in ESLint is probably going to be in ESLint 7, if they are able to get it done (unfortunately I don't have time to dig into all the changes they need) - there's more work than just adding the global as some of the rules need to support it.

I'm therefore going to propose we leave the status quo as-is until ESLint 7 is released, and then tidy up after that.

Comment 3

[Julian Descottes [:jdescottes]]

Sounds good, thanks for following up Mark!

Comment 4

[Mark Banner (:standard8)]

I'm going to munge this into a meta to include the other fancy new javascript tools - the nullish coalesce operator and the conditional chaining operator.

There's some ideas and discussions going on in other bugs that we'll track here.

Comment 5

[Mark Banner (:standard8)]

Note: Nullish coalesce operator and conditional chaining are now supported with thanks to @Mossop and @Mardak.

I think we'll have to wait for the next ESLint major version to get the globalThis support.

Comment 6

[Mark Banner (:standard8)]

Bug 1620537 just landed ESLint 7.5.0 which adds full support for globalThis.