Adopt ES module syntax

What does this MR do?

Replaces all CJS module syntax:

// foo.js
module.exports = class Foo { /* ... */ };

// bar.js
const Foo = require('foo');

with ES module syntax:

// foo.js
export default class Foo ( /* ... */ };

// bar.js
import Foo from 'foo';

Are there points in the code the reviewer needs to double check?

Why was this MR needed?

ES module syntax is supported natively in webpack and allows for declarative, statically analyzed dependencies. It will also allow us to do fun things like tree shaking.

Screenshots (if relevant)

n/a

Does this MR meet the acceptance criteria?

• Changelog entry added
• Documentation created/updated
• Tests
  • All builds are passing
• Conform by the merge request performance guides
• Conform by the style guides
• Branch has no merge conflicts with master (if it does - rebase it please)
• Squashed related commits together

What are the relevant issue numbers?

#27486 (moved)

added 4 commits

• 14015d4d - switch all frontend assets to ES module syntax
• 3b0bdf34 - use ES module export syntax in place of CJS module.exports
• 860c25bd - utilize expose-loader to export jQuery on window for legacy jQuery plugins
• a2abf234 - fix failing test due to import syntax

Compare with previous version

added 1 commit

• f60d1cfe - rename application.js to entry.js

Compare with previous version

added 825 commits

• f60d1cfe...1110b2f1 - 822 commits from branch master
• b4a5a9bb - fix failing test due to import syntax
• 758fe969 - Merge branch 'master' into adopt-es-module-syntax
• fb79e2cb - fix additional CJS uses after merge

Compare with previous version

added 2 commits

• e0aab1f8 - fix eslint errors
• 328cee1c - fix module exports

Compare with previous version

added 1 commit

• c2c55e6d - fix module exports

Compare with previous version

added 1 commit

• 918a73af - fix global Vue dependency in issuable bundle

Compare with previous version

starting fresh by resetting on the master branch... too many changes have been made since I last rebased this and it's easier to start over

added 584 commits

• 918a73af...b26d4d2a - 584 commits from branch master

Compare with previous version

added 4011 commits

• b26d4d2a...ba44ca13 - 4011 commits from branch master

Compare with previous version

added 7 commits

• a8b5878b - update boards_bundle to ES module syntax
• 4322d3c2 - update cycle_analytics_bundle to ES module syntax
• c594ed49 - update diff_notes_bundle to ES module syntax
• 0fce2df7 - update filtered_search to ES module syntax
• f5ad1dcb - update shortcuts scripts to use ES module syntax
• 5bd54918 - update remaining uses of CJS syntax to ES module syntax
• 6c695c52 - update dispatcher.js to use ES module syntax

Compare with previous version

added 2 commits

• 283f968e - update frontend specs to use ES module syntax
• fc4cabca - update test_bundle to use ES module syntax

Compare with previous version

added 1 commit

• f68a3f3f - fix implicit window object reference within gl_form_spec

Compare with previous version

marked the checklist item Documentation created/updated as completed

added 2 commits

• 337acf4b - fix eslint failures
• 83f8a91c - refactor instances of CJS module.exports to ES module syntax

Compare with previous version

added 1 commit

• 8892e66c - update linter to catch uses of commonjs syntax

Compare with previous version

added 1 commit

• 97724e62 - fix eslint violation

Compare with previous version

changed milestone to %9.3

@filipa can you review this and gitlab-ee!1913?

assigned to @filipa

changed the description

marked the checklist item All builds are passing as completed

resolved all discussions

@mikegreiling thank you for this!

The code lgtm, I run it locally and found one problem: (not sure if it was introduced by this MR since it is 266 commits behind master)

• Edit a file, save changes with the Start a new merge request with these changes checked, and no merge request is created, it commits to master directly

Can you please confirm this was not introduced by this MR? Thanks!

assigned to @mikegreiling

@filipa I ran through the steps you outlined and can confirm that it does behave that way, but master does this as well so I think that is a separate issue.

I think you are supposed to change "target branch" to something other than "master" for that "Start a new merge request with these changes" to have any effect.

Can you merge this?

assigned to @filipa

@filipa I created a new issue for the bug you described here: #32703 (closed)

Thank you @mikegreiling

approved this merge request

merged

mentioned in commit b261fb7b