feat(eslint-plugin): add extension rule no-loss-of-precision

[yeonjuan]

Fixes #2076

[typescript-eslint]

Thanks for the PR, @yeonjuan!

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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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[yeonjuan]

The CI is failed because "typescript-eslint" use eslint v7.0.0.
May I create another PR for upgrade eslint to v7.2.0?

[bradzacher]

feel free to bump the version in this PR - it's only a minor bump so it's safe.

[codecov]

Codecov Report

Merging #2196 into master will decrease coverage by 0.00%.
The diff coverage is 91.66%.

@@            Coverage Diff             @@
##           master    #2196      +/-   ##
==========================================
- Coverage   93.39%   93.39%   -0.01%     
==========================================
  Files         173      174       +1     
  Lines        7871     7883      +12     
  Branches     2247     2251       +4     
==========================================
+ Hits         7351     7362      +11     
  Misses        247      247              
- Partials      273      274       +1     

Flag	Coverage Δ
#unittest	93.39% <91.66%> (-0.01%)	⬇️

Impacted Files	Coverage Δ
packages/eslint-plugin/src/configs/all.ts	100.00% <ø> (ø)
...es/eslint-plugin/src/rules/no-loss-of-precision.ts	91.66% <91.66%> (ø)

[bradzacher]

We need to guard against this not existing in <7.2.0, so that it only errors if a user attempts to actually use the rule in an old version of ESLint, and not if the user attempts to use the plugin.

This is why the integration test is failing.

Something like this (hack) will probably do:

import BaseRuleType from 'eslint/lib/rules/no-loss-of-precision';
import * as util from '../util';

const baseRule = ((): BaseRuleType | null => {
  try {
    return require('eslint/lib/rules/no-loss-of-precision');
  } catch {
    return null;
  }
}());

// ...
create(context) {
  if (baseRule == null) {
    throw new Error('@typescript-eslint/no-loss-of-precision requires at least ESLint v7.2.0');
  }
}

[yeonjuan]

@bradzacher thanks for the solution. :)

[bradzacher]

LGTM - thanks!