Tooling: install the jsx-a11y plugin

.github/workflows/lint.yml

@@ -0,0 +1,48 @@
+name: "(Lint): CSS, JS, PHP"
+
+on:
+  pull_request:
+    types: [opened, synchronize, reopened, labeled]
+  push:
+    branches:
+      - 'core'
+      - 'pro'
+    paths-ignore:
+      - '**.md'
+      - '**.txt'
+      - '.gitignore'
+      - 'docs/**'
+  workflow_dispatch:
+
+permissions:
+  contents: read
+
+concurrency:
+  group: lint-${{ github.workflow }}-${{ github.event_name }}-${{ github.event_name == 'pull_request' && github.event.pull_request.number || github.ref }}
+  cancel-in-progress: true
+
+jobs:
+  lint:
+    name: stylelint, eslint, phpcs
+    runs-on: ubuntu-22.04
+    steps:
+      - name: Checkout source code
+        uses: actions/checkout@v4
+
+      - name: Set up Node.js
+        uses: actions/setup-node@v4
+        with:
+          node-version-file: .node-version
+          cache: 'npm'
+
+      - name: Install npm dependencies
+        run: npm ci
+
+      - name: Run Stylelint
+        run: npm run lint:styles
+
+      - name: Run ESLint
+        run: npm run lint:js
+
+      - name: Run PHP CS
+        run: npm run lint:php

eslint.config.mjs

@@ -6,6 +6,7 @@ import eslintTs from 'typescript-eslint'
 import stylistic from '@stylistic/eslint-plugin'
 import reactHooks from 'eslint-plugin-react-hooks'
 import importPlugin from 'eslint-plugin-import'
+import jsxA11yPlugin from 'eslint-plugin-jsx-a11y'
 import reactPlugin from 'eslint-plugin-react'
 import { FlatCompat } from '@eslint/eslintrc'
 
@@ -21,6 +22,7 @@ export default eslintTs.config(
 	...compat.extends('plugin:react-hooks/recommended'),
 	reactPlugin.configs.flat.recommended,
 	importPlugin.flatConfigs.recommended,
+	jsxA11yPlugin.flatConfigs.strict,
 	{
 		plugins: { 'react-hooks': reactHooks },
 		rules: reactHooks.configs.recommended.rules,
@@ -127,7 +129,30 @@ export default eslintTs.config(
 			'prefer-named-capture-group': 'error',
 			'prefer-template': 'error',
 			'sort-imports': ['error', { ignoreDeclarationSort: true }],
-			'yoda': ['error', 'always']
+			'yoda': ['error', 'always'],
+			// Accessibility rules.
+			'jsx-a11y/alt-text': 'error',
+			'jsx-a11y/anchor-has-content': 'error',
+			'jsx-a11y/anchor-is-valid': 'error',
+			'jsx-a11y/aria-props': 'error',
+			'jsx-a11y/aria-proptypes': 'error',
+			'jsx-a11y/aria-role': 'error',
+			'jsx-a11y/aria-unsupported-elements': 'error',
+			'jsx-a11y/click-events-have-key-events': 'error',
+			'jsx-a11y/control-has-associated-label': 'error',
+			'jsx-a11y/heading-has-content': 'error',
+			'jsx-a11y/iframe-has-title': 'error',
+			'jsx-a11y/img-redundant-alt': 'error',
+			'jsx-a11y/interactive-supports-focus': 'error',
+			'jsx-a11y/label-has-associated-control': 'error',
+			'jsx-a11y/no-autofocus': 'error',
+			'jsx-a11y/no-noninteractive-element-interactions': 'error',
+			'jsx-a11y/no-noninteractive-tabindex': 'error',
+			'jsx-a11y/no-redundant-roles': 'error',
+			'jsx-a11y/no-static-element-interactions': 'error',
+			'jsx-a11y/role-has-required-aria-props': 'error',
+			'jsx-a11y/role-supports-aria-props': 'error',
+			'jsx-a11y/tabindex-no-positive': 'error'
 		}
 	},
 	{