[code-infra] Create examples eslint rule (#42170)

Signed-off-by: Jan Potoms <2109932+Janpot@users.noreply.github.com>
Co-authored-by: Jan Potoms <2109932+Janpot@users.noreply.github.com>

.eslintrc.js

@@ -299,7 +299,7 @@ module.exports = {
     },
     // Next.js entry points pages
     {
-      files: ['docs/pages/**/*.js'],
+      files: ['docs/pages/**/*{.tsx,.js}'],
       rules: {
         'react/prop-types': 'off',
       },
@@ -473,5 +473,36 @@ module.exports = {
         'import/prefer-default-export': 'off',
       },
     },
+    {
+      /**
+       * Examples are for demonstration purposes and should not be considered a part of the library.
+       * They don't contain ESLint setup, so we don't want them to contain ESLint directives
+       * We do, however, want to keep the rules in place to ensure the examples are following
+       * a reasonably similar code style as the library.
+       */
+      files: ['examples/**/*'],
+      rules: {
+        'no-console': 'off',
+        'no-underscore-dangle': 'off',
+        'import/no-unresolved': 'off',
+        'import/namespace': 'off',
+        'import/extensions': 'off',
+        'import/named': 'off',
+        'import/no-duplicates': 'off',
+        'import/no-named-as-default': 'off',
+        'import/default': 'off',
+        'import/no-named-as-default-member': 'off',
+        'import/order': 'off',
+        // Reset the default until https://github.com/jsx-eslint/eslint-plugin-react/issues/3672 is fixed.
+        'react/jsx-no-target-blank': ['error', { allowReferrer: false }],
+      },
+    },
+    {
+      // TODO, move rule to be global, propagate: https://github.com/mui/material-ui/issues/42169
+      files: ['examples/pigment-css-remix-ts/**/*'],
+      rules: {
+        'react/react-in-jsx-scope': 'off',
+      },
+    },
   ],
 };

examples/material-ui-express-ssr/server.js

@@ -66,6 +66,5 @@ app.use(handleRender);
 
 const port = 3000;
 app.listen(port, () => {
-  // eslint-disable-next-line no-console
   console.log(`Listening on ${port}`);
 });

examples/material-ui-remix-ts/app/root.tsx

@@ -31,7 +31,6 @@ const Document = withEmotionCache(({ children, title }: DocumentProps, emotionCa
     const tags = emotionCache.sheet.tags;
     emotionCache.sheet.flush();
     tags.forEach((tag) => {
-      // eslint-disable-next-line no-underscore-dangle
       (emotionCache.sheet as any)._insertTag(tag);
     });
     // reset cache to reapply global styles