As part of rolling out ESLint across the tree, we should enable it for dom/url.

To help Mozilla out with this bug, here's the steps:

1. Comment here on the bug that you want to volunteer to help. I (or someone else) will assign it to you.
2. Download and build the Firefox source code, see the docs for details. An artifact build is all you need.
   • If you have any problems, please ask on IRC in the #introduction channel. They're there to help you get started.
   • You can also read the Developer Guide, which has answers to most development questions.
3. Start working on this bug
   • Please note:
     • We want to end up with two separate commits. One with the automatic changes, the second with the manual changes.
     • Although you'll change .eslintignore at the start, only the second commit should have the .eslintignore changes. Please follow the suggested commands closely.
   • Here's what to do:
     1. In .eslintignore, remove the dom/url/** line.
     2. Run eslint ./mach eslint --fix dom/url
        • This should fix some of the issues.
     3. Inspect the diff to make sure that the indentation of the lines surrounding the changes look ok.
     4. Create a commit of the work so far. Note the extra dom/url at the end (this avoids committing .eslintignore at this stage)
        • $ hg commit -m "Bug nnn - Enable ESLint for dom/url (automatic changes). r?Standard8" dom/url
     5. For the remaining issues, you'll need to fix them by hand. To find them, run ./mach eslint dom/url.
        • Most of those should be reasonably easy to understand, but there's more information on some specific bits (especially no-undef) here and here.
     6. Create a second commit of the manual changes, note, there's no directory specifier this time, so .eslintignore will be included.
        • $ hg commit -m "Bug nnn - Enable ESLint for dom/url (manual changes). r?Standard8
     7. Post the two commits via phabricator. Please use moz-phab to submit them.
4. Once the patches are submitted, I'll take a look. If there's any changes necessary I'll comment in Phabricator, so be prepared to update the patches. If there's no changes, I'll request review from a dom peer, so there may still be more to go.
5. Once we're happy with the changes, I'll push it to autoland - our integration branch. Your code will then soon be shipping to Firefox users worldwide!
6. Now you get to think about what kind of bug you'd like to work on next. Let me know what you're interested in and I can help you find your next contribution.

Hey Mark, I'd like to work on this please.

Hi @danielleleb12, good to hear from you again.

Hey Mark! Creating a patch now. There were a few files with issues that I wasn't totally sure about - looking forward to your feedback on how some of these issues should properly be solved!

Depends on D22736

https://hg.mozilla.org/mozilla-central/rev/f87b1c69a88d
https://hg.mozilla.org/mozilla-central/rev/e263d6805e14