Adds enforcement of WordPress's i18n rules

[mhkuu]

Context

• We want to adhere to WordPress's i18n rules, throughout our plugin. This PR adds an eslint plugin to our generic eslint config for that purpose. As a result, we can also use this configuration elsewhere.

Summary

This PR can be summarized in the following changelog entry:

• Adds enforcement of WordPress's i18n rules.
• [yoastseo] Adds enforcement of WordPress's i18n rules.

Relevant technical choices:

• We use this package, however, it's still written for eslint 8.
• So, we added some compatibility utilities as per this article to resolve that. See also this implementation.

Test instructions

Test instructions for the acceptance test before the PR gets merged

This PR can be acceptance tested by following these steps:

• Run the linter with yarn lint, confirm the number of warnings is below the threshold.
• Run the tests with yarn test, confirm they all pass.
• Do a smoke test in the application.

Relevant test scenarios

• Changes should be tested with the browser console open
• Changes should be tested on different posts/pages/taxonomies/custom post types/custom taxonomies
• Changes should be tested on different editors (Default Block/Gutenberg/Classic/Elementor/other)
• Changes should be tested on different browsers
• Changes should be tested on multisite

Test instructions for QA when the code is in the RC

• QA should use the same steps as above.

QA can test this PR by following these steps:

Impact check

This PR affects the following parts of the plugin, which may require extra testing:

• No further impact.

UI changes

• This PR changes the UI in the plugin. I have added the 'UI change' label to this PR.

Other environments

• This PR also affects Shopify. I have added a changelog entry starting with [shopify-seo], added test instructions for Shopify and attached the Shopify label to this PR.

Documentation

• I have written documentation for this change. For example, comments in the Relevant technical choices, comments in the code, documentation on Confluence / shared Google Drive / Yoast developer portal, or other.

Quality assurance

• I have tested this code to the best of my abilities.
• During testing, I had activated all plugins that Yoast SEO provides integrations for.
• I have added unit tests to verify the code works as intended.
• If any part of the code is behind a feature flag, my test instructions also cover cases where the feature flag is switched off.
• I have written this PR in accordance with my team's definition of done.
• I have checked that the base branch is correctly set.

Innovation

• No innovation project is applicable for this PR.
• This PR falls under an innovation project. I have attached the innovation label.
• I have added my hours to the WBSO document.

Fixes https://github.com/Yoast/lingo-other-tasks/issues/456

[rohans456]

This PR is a solid step towards improving the i18n quality of the yoastseo package. The changes are well-structured, and the use of compatibility tools (flatCompat.extends and fixupConfigRules) is correctly implemented. I’ve suggested a small optimization to reduce redundant processing and improve performance.

[rohans456]

• Calling flatCompat.extends(...) inside an array spread could add unnecessary processing overhead.
• Consider storing the result in a variable before applying fixupConfigRules, like:

const wordpressRules = flatCompat.extends("plugin:@wordpress/eslint-plugin/i18n");
...fixupConfigRules(wordpressRules),

[mhkuu]

Thanks, I've applied this when moving the rules to the generic config in packages/eslint/default.mjs 🎉

[github-actions]

A merge conflict has been detected for the proposed code changes in this PR. Please resolve the conflict by either rebasing the PR or merging in changes from the base branch.

[github-actions]

@mhkuu Please be aware that following packages have been abandoned and are not actively maintained anymore:

Package name	Path
@yoast/babel-preset	packages/babel-preset
@yoast/components	packages/components
@yoast/e2e-tests	packages/e2e-tests
@yoast/helpers	packages/helpers
@yoast/jest-preset	packages/jest-preset
@yoast/style-guide	packages/style-guide

Please consider using the other packages instead.

[coveralls]

Pull Request Test Coverage Report for Build 5b91beb8f200401be1924eae61d8391df50808f0

Details

• 11 of 18 (61.11%) changed or added relevant lines in 9 files are covered.
• 2 unchanged lines in 2 files lost coverage.
• Overall coverage decreased (-0.001%) to 53.216%

---

Changes Missing Coverage	Covered Lines	Changed/Added Lines	%
packages/js/src/components/WincherPerformanceReport.js	0	1	0.0%
packages/js/src/insights/components/flesch-reading-ease.js	0	1	0.0%
packages/js/src/first-time-configuration/tailwind-components/steps/site-representation/person-section.js	0	2	0.0%
packages/js/src/structured-data-blocks/how-to/legacy/utils/8.2.js	0	3	0.0%

Files with Coverage Reduction	New Missed Lines	%
packages/js/src/first-time-configuration/tailwind-components/steps/site-representation/person-section.js	1	0.0%
packages/js/src/import.js	1	0.0%

Totals
Change from base Build 61f494b7eed6e03cd1518dc37ed23c600b4c19fd:	-0.001%
Covered Lines:	30280
Relevant Lines:	57691

---

💛 - Coveralls

[mhkuu]

After a discussion with @FAMarfuaty we decided to move the configuration to the generic ESLint config in packages/eslint/default.mjs. That was done in 9393d39, also applying the suggestion from the code review above. Then, in 7b5b390, the errors were resolved for all the other JS packages, and in 4093f43, the unit tests were updated.

[mhkuu]

CR/ACC by @rohans456: ✅