fix(eslint-plugin): [prefer-ts-expect-error] support block comments

[yasarsid]

Fixes #2531

Overview

The support for prefer-ts-expect-error was restricted to only single line comments.

This PR looks to expand the support for prefer-ts-expect-error for block comments also.

Approach

The approach revolved around changing the regex for recognizing the valid cases of @ts-ignore and removing a check for block comments.

Additionally, the Rulefixer for single line comments and block comments has a little different behavior.

Checklist

• Add UTs corresponding to change
• Change rule documentation corresponding to change

[typescript-eslint]

Thanks for the PR, @yasarsid!

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!

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[codecov]

Codecov Report

Merging #2541 into master will increase coverage by 0.01%.
The diff coverage is n/a.

@@            Coverage Diff             @@
##           master    #2541      +/-   ##
==========================================
+ Coverage   92.81%   92.83%   +0.01%     
==========================================
  Files         290      290              
  Lines        9453     9516      +63     
  Branches     2647     2666      +19     
==========================================
+ Hits         8774     8834      +60     
- Misses        322      323       +1     
- Partials      357      359       +2     

Flag	Coverage Δ
#unittest	92.83% <ø> (+0.01%)	⬆️

Flags with carried forward coverage won't be shown. Click here to find out more.

Impacted Files	Coverage Δ
.../eslint-plugin/src/rules/prefer-ts-expect-error.ts	100.00% <ø> (ø)
...ackages/eslint-plugin/src/rules/no-implied-eval.ts	93.75% <0.00%> (-2.81%)	⬇️
packages/eslint-plugin/src/rules/return-await.ts	95.69% <0.00%> (-0.08%)	⬇️
packages/experimental-utils/src/ts-eslint/Scope.ts	100.00% <0.00%> (ø)
...es/eslint-plugin/src/rules/no-use-before-define.ts	94.36% <0.00%> (ø)
...kages/eslint-plugin/src/rules/naming-convention.ts	89.30% <0.00%> (+0.14%)	⬆️
packages/eslint-plugin/src/rules/no-unused-vars.ts	93.06% <0.00%> (+0.21%)	⬆️
...es/eslint-plugin/src/rules/prefer-function-type.ts	96.29% <0.00%> (+1.17%)	⬆️

[bradzacher]

this is not valid code - the expect error does not apply to the next line in either of these cases
repl

[yasarsid]

Thanks for pointing it out.

I think I got mixed up with the following code repl

/** 
 *  
 * @ts-ignore */
let value: string = 1

Corrected and added additional test cases for the same.

[bradzacher]

this is not valid code - the expect error does not apply to the next line in either of these cases
repl

[yasarsid]

Correct now

[bradzacher]

LGTM - thanks for your contribution