feat(eslint-plugin): add extension rule keyword-spacing

[OoDeLally]

Addressing my own issue
fixes #1729

I am totally new to this, so feel free to suggest me improvements.

[typescript-eslint]

Thanks for the PR, @OoDeLally!

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[G-Rath]

I've just done a basic lookover, focusing on your comments to help unblock you until someone can do a proper review :)

Happy to help if you have questions!

[OoDeLally]

@G-Rath Ok, thanks for your comments. I'm now importing the base rule, it simplifies a bit.

[G-Rath]

Looking good!

Now that you're using the base rule, you can also drop the majority of the tests, since we don't need to re-test what eslint has already tested 😉

[OoDeLally]

I'm now re-declaring the list of keywords both in typing and in string array.

[OoDeLally]

What is the deal with Semantic Pull Request? What is wrong with my title?

[OoDeLally]

How is that codecov thingy actionable? Anything I should do about it?

[bradzacher]

What is the deal with Semantic Pull Request? What is wrong with my title?

You were missing a : after your ). I updated appropriately.

How is that codecov thingy actionable? Anything I should do about it?

If you click through to the details on the codecov site, it'll show you what branches of your code have not been hit by tests.
i.e. clicking on the keyword-spacing.ts file in the codecov comment takes you here: https://codecov.io/gh/typescript-eslint/typescript-eslint/pull/1739/diff?src=pr&el=tree#diff-cGFja2FnZXMvZXNsaW50LXBsdWdpbi9zcmMvcnVsZXMva2V5d29yZC1zcGFjaW5nLnRz

Scrolling through that report, green means all good, yellow means one of the branches was missed, and red means all of the branches were missed.
I.e. looking at the report, theres missed lines for reporting expectedAfter and unexpectedAfter.

[OoDeLally]

Would you know a way to avoid having to declare the option typing twice (in eslint-rule.d.ts and in keyword-spacing.ts) ?
I see no way of declaring it at one place and import them from the other place. Tried many ways, without success.

[bradzacher]

a few comments, you might be able to simplify this by being a bit hacky - see my last comment.

[codecov]

Codecov Report

Merging #1739 into master will increase coverage by 0.00%.
The diff coverage is 100.00%.

@@           Coverage Diff           @@
##           master    #1739   +/-   ##
=======================================
  Coverage   94.37%   94.38%           
=======================================
  Files         164      165    +1     
  Lines        7572     7585   +13     
  Branches     2175     2175           
=======================================
+ Hits         7146     7159   +13     
  Misses        183      183           
  Partials      243      243           

Flag	Coverage Δ
#unittest	94.38% <100.00%> (+<0.01%)	⬆️

Impacted Files	Coverage Δ
...ackages/eslint-plugin/src/rules/keyword-spacing.ts	100.00% <100.00%> (ø)

[OoDeLally]

Looking at the rule's source code, you might be able to get away with just this fudge code for this extension:

This seems to fail every test with:

  ● keyword-spacing › invalid › const foo = {}as {}

    TypeError: Cannot read property 'before' of undefined
    Occurred while linting file.ts:1

      at checkSpacingBefore (../../node_modules/eslint/lib/rules/keyword-spacing.js:268:21)
      at Object.checkSpacingForImportNamespaceSpecifier [as ImportNamespaceSpecifier] (../../node_modules/eslint/lib/rules/keyword-spacing.js:466:13)
      at TSAsExpression (src/rules/keyword-spacing.ts:3054:19)

The error is in lib/rules/keyword-spacing.js at

        function checkSpacingBefore(token, pattern) {
            checkMethodMap[token.value].before(token, pattern || PREV_TOKEN);
        }

I don't really understand what is going on, so I wouldn't risk replacing it.

If you find a way to make it work, I'll be happy to simplify it.

[bradzacher]

Thanks!