feat(eslint-plugin): add extension rule init-declarations

[anikethsaha]

fixes #1811

• init-declarations
• added tests for declaring of typed variables
• docs

[typescript-eslint]

Thanks for the PR, @anikethsaha!

typescript-eslint is a 100% community driven project, and we are incredibly grateful that you are contributing to that community.

The core maintainers work on this in their personal time, so please understand that it may not be possible for them to review your work immediately.

Thanks again!

---

🙏 Please, if you or your company is finding typescript-eslint valuable, help us sustain the project by sponsoring it transparently on https://opencollective.com/typescript-eslint. As a thank you, your profile/company logo will be added to our main README which receives thousands of unique visitors per day.

[anikethsaha]

@bradzacher messageIds is simply extending string and that is causing error for test file's messaged of invalid cases. Any workaround.? Is it ok to change the type in ruletester to string instead of extending it .

similar for errors.type

[bradzacher]

make sure you validate your code locally and fix the errors.

https://github.com/typescript-eslint/typescript-eslint/blob/master/CONTRIBUTING.md#validating-your-changes

[codecov]

Codecov Report

Merging #1814 into master will decrease coverage by 0.02%.
The diff coverage is 81.25%.

@@            Coverage Diff             @@
##           master    #1814      +/-   ##
==========================================
- Coverage   94.38%   94.36%   -0.03%     
==========================================
  Files         165      166       +1     
  Lines        7592     7608      +16     
  Branches     2178     2185       +7     
==========================================
+ Hits         7166     7179      +13     
  Misses        183      183              
- Partials      243      246       +3     

Flag	Coverage Δ
#unittest	94.36% <81.25%> (-0.03%)	⬇️

Impacted Files	Coverage Δ
...kages/eslint-plugin/src/rules/init-declarations.ts	81.25% <81.25%> (ø)

[anikethsaha]

@bradzacher looks like there is some auth issue, I cant push to this branch after reading

[bradzacher]

Make sure your local is up to date with the remote before pushing, or try force pushing if you want to overwrite the remote.

[anikethsaha]

I did rebase and after that its coming. Its up to date with upstream

[anikethsaha]

@bradzacher I did add some more tests but the diff coverage is still the same as before adding them
any suggestion ?

[bradzacher]

https://codecov.io/gh/typescript-eslint/typescript-eslint/pull/1814/diff

The lines marked with yellow are branches that haven't been tested.

I.e. looking at your code + tests, you've got code that handles module declarations, but no tests for it.

[anikethsaha]

@bradzacher I don't know how to particularly test those lines. I did add some test cases to cover those conditions.

[bradzacher]

I don't know how to particularly test those lines.

In codecov, yellow means that one branch of a conditional check has been tested, but not the other branch.

So looking at the code in question:

if (
  node.parent?.type === AST_NODE_TYPES.TSModuleBlock &&
  node.parent?.parent?.type === AST_NODE_TYPES.TSModuleDeclaration &&
  node.parent?.parent?.declare
) {
  return;
}

What is this if statement doing? What is it guarding against?
Compare it with your tests - which of the two branches are you testing, and which are you not?

(this is not me trying to be snarky here - I'm trying to drop a hint without giving you the answer 😄)

---

Another thing I see you doing in your code a lot is you're using unnecessary optional chains ?..
The typescript types are all correct - so you only need do use an optional chain if the field is nullish. Codecov has no way to understand this though - it just sees an optional chain as a branch that needs to be tested.

eg you've got if (node?.declare) { return }, but node is never nullish, so the ?. is unnecessary.

[anikethsaha]

(this is not me trying to be snarky here - I'm trying to drop a hint without giving you the answer 😄)

😅

I will give another try 👍

[anikethsaha]

@bradzacher
I did add some tests for those if statements in the latest commits
ed71f47

de1544f

07950f6

anything missing, a hint would be great

[bradzacher]

Those test are sufficient - the reason codecov is reporting lower is because of the optional chain.
The parent is never nullable, so there's no way to test that branch - just ignore it. Your coverage is sufficient.

The branch target isn't a hard merge blocker. It's a guideline to help ensure people do enough tests and help me review that the tests cover the cases.

[anikethsaha]

the reason codecov is reporting lower is because of the optional chain.

I doubted that. idk even codecov supports the optional chaining or not

The branch target isn't a hard merge blocker. It's a guideline to help ensure people do enough tests and help me review that the tests cover the cases.

cool, 👍

[bradzacher]

LGTM - thanks!