chore(eslint): More work on the root .eslintrc

* Remove the site-specific and `packages/new-design`-specific `.eslintrc` files
* Use `eslint-config-next` where appropriate (this fixes linting for sites/shared, bringing it in line with the other sites)
* Be more strict about which envs/globals are allowed in any given JavaScript file; assume none by default.

.eslintrc.cjs

@@ -1,7 +1,25 @@
+const nodeFiles = [
+  '**/build.dflt.{js,mjs,cjs}',
+  '**/build.{js,mjs,cjs}',
+  '**/config/**',
+  '**/prebuild.{js,mjs,cjs}',
+  '**/prebuild/**',
+  '**/scripts/**',
+  'packages/new-design/lib/**',
+  'sites/backend/**',
+  'sites/*/mdx/**',
+  'sites/*/themes/**',
+]
+const frontendFiles = [
+  '**/components/**',
+  '**/hooks/**',
+  '**/pages/**',
+  '**/page-templates/**',
+]
+
 module.exports = {
   extends: 'eslint:recommended',
   env: {
-    browser: true,
     es2021: true,
   },
   // Required when using experimental EcmaScript features
@@ -17,13 +35,48 @@ module.exports = {
   },
   rules: {},
   overrides: [
-    // JavaScript source files
+    // Partitioned JavaScript files
+    {
+      files: nodeFiles,
+      env: {
+        node: true,
+      },
+      rules: {
+        'no-console': 'off',
+      },
+    },
+    {
+      files: frontendFiles,
+      excludedFiles: nodeFiles,
+      extends: ['next/core-web-vitals'],
+      env: {
+        // We can be stricter than 'next/core-web-vitals' is
+        node: false,
+      },
+    },
+    {
+      files: '**',
+      excludedFiles: [].concat(nodeFiles, frontendFiles),
+      env: {
+        'shared-node-browser': true,
+      },
+    },
+    // Additional globals for JavaScript files that happen to be CommonJS.
+    // Only allowed in *.cjs files, not *.js files, because we probably want to move towards
+    // a `"type": "module"` future where any CommonJS files would have to have .cjs extensions.
     {
       files: ['**/*.cjs'],
       env: {
         commonjs: true,
       },
     },
+    // Additional globals for JavaScript files that happen to contain Mocha tests
+    {
+      files: ['**/tests/**', '**/*.test.mjs'],
+      env: {
+        mocha: true,
+      },
+    },
 
     // JSON files
     {
@@ -41,7 +94,7 @@ module.exports = {
 
     // Markdown files
     {
-      files: ['**/*.md'],
+      files: ['**/markdown/**', '**/*.md'],
       plugins: ['markdown'],
       processor: 'markdown/markdown',
     },
@@ -56,10 +109,4 @@ module.exports = {
       },
     },
   ],
-  globals: {
-    it: 'readonly',
-    describe: 'readonly',
-    process: 'readonly',
-    __dirname: 'readonly',
-  },
 }

package.json

@@ -75,6 +75,7 @@
     "esbuild": "^0.15.3",
     "esbuild-plugin-yaml": "^0.0.1",
     "eslint": "^8.23.1",
+    "eslint-config-next": "^12.3.1",
     "eslint-plugin-jsonc": "^2.4.0",
     "eslint-plugin-markdown": "^3.0.0",
     "eslint-plugin-yaml": "^0.5.0",

packages/new-design/.eslintrc.yml

@@ -1,18 +0,0 @@
-env:
-  browser: true
-  es2021: true
-extends: eslint:recommended
-overrides:
-  - files: ["*.yaml", "*.yml"]
-    plugins: ["yaml"]
-    extends: ["plugin:yaml/recommended"]
-parserOptions:
-  ecmaVersion: latest
-  sourceType: module
-rules: {}
-globals:
-  it: readonly
-  describe: readonly
-  process: readonly
-  __dirname: readonly
-

sites/dev/.eslintrc.json

@@ -1,3 +0,0 @@
-{
-  "extends": "next/core-web-vitals"
-}

sites/lab/.eslintrc.json

@@ -1,3 +0,0 @@
-{
-  "extends": "next/core-web-vitals"
-}

sites/org/.eslintrc.json

@@ -1,3 +0,0 @@
-{
-  "extends": "next/core-web-vitals"
-}

sites/shared/.eslintrc.yml

@@ -1,18 +0,0 @@
-env:
-  browser: true
-  es2021: true
-extends:
-  - eslint:recommended
-  - plugin:react/recommended
-overrides: []
-parserOptions:
-  ecmaVersion: latest
-  sourceType: module
-plugins:
-  - react
-rules:
-  react/prop-types: off
-  react/react-in-jsx-scope: off
-globals:
-  module: readonly
-

yarn.lock

@@ -7823,7 +7823,7 @@ escodegen@^2.0.0:
   optionalDependencies:
     source-map "~0.6.1"
 
-eslint-config-next@12.3.1:
+eslint-config-next@12.3.1, eslint-config-next@^12.3.1:
   version "12.3.1"
   resolved "https://registry.yarnpkg.com/eslint-config-next/-/eslint-config-next-12.3.1.tgz#5d4eb0b7903cea81fd0d5106601d3afb0a453ff4"
   integrity sha512-EN/xwKPU6jz1G0Qi6Bd/BqMnHLyRAL0VsaQaWA7F3KkjAgZHi4f1uL1JKGWNxdQpHTW/sdGONBd0bzxUka/DJg==