Add linting, spellcheck, and editor configs

Add project tooling and editor configs: new cspell config and GitHub spellcheck workflow, .prettierignore, .nvmrc and VSCode recommendations/settings. Tighten linters and CI: expand .eslintrc rules, update super-linter/codeql YAML headers, enable an HTMLHint rule change. Update package.json: add htmlhint and cspell scripts, bump prettier, and record Volta node version. Apply small code hygiene changes to source and minified JS ("use strict" and clearer if/else), and normalize README badge text.

Author: coliff

.cspell.json

@@ -0,0 +1,19 @@
+{
+  "version": "0.2",
+  "words": [
+    "christianoliff",
+    "fediverse",
+    "fnames",
+    "Oliff",
+    "stylelint",
+    "tagname",
+    "unspaced"
+  ],
+  "allowCompoundWords": true,
+  "language": "en,en-US",
+  "ignorePaths": [
+    ".cspell.json",
+    "**/node_modules/**"
+  ],
+  "useGitignore": true
+}

.eslintrc.json

@@ -1,21 +1,50 @@
 {
   "root": true,
   "extends": ["eslint:recommended", "prettier"],
+  "ignorePatterns": ["dark-mode-switch.min.js"],
   "env": {
     "browser": true,
     "es6": true
   },
   "parserOptions": {
-    "ecmaVersion": 2015,
+    "ecmaVersion": 2020,
     "sourceType": "script"
   },
   "rules": {
+    "strict": ["error", "global"],
+    "curly": ["error", "all"],
+    "eqeqeq": ["error", "always"],
+    "no-alert": "error",
+    "no-caller": "error",
+    "no-console": "error",
+    "no-else-return": "error",
+    "no-eval": "error",
+    "no-extend-native": "error",
+    "no-extra-bind": "error",
+    "no-implicit-coercion": "error",
+    "no-implied-eval": "error",
+    "no-iterator": "error",
+    "no-labels": "error",
+    "no-lone-blocks": "error",
+    "no-multi-str": "error",
+    "no-new-func": "error",
+    "no-new-wrappers": "error",
+    "no-octal-escape": "error",
+    "no-proto": "error",
+    "no-return-assign": "error",
+    "no-script-url": "error",
+    "no-self-compare": "error",
+    "no-sequences": "error",
+    "no-throw-literal": "error",
     "no-undef": "error",
+    "no-unused-expressions": "error",
     "no-unused-vars": "error",
-    "no-console": "warn",
-    "eqeqeq": ["error", "always"],
-    "curly": ["error", "all"],
+    "no-useless-call": "error",
+    "no-useless-concat": "error",
     "no-var": "off",
-    "prefer-const": "off"
+    "prefer-const": "off",
+    "radix": "error",
+    "wrap-iife": ["error", "outside"],
+    "yoda": "error"
   }
 }

.github/workflows/codeql-analysis.yml

@@ -1,3 +1,4 @@
+---
 name: "CodeQL"
 
 on:

.github/workflows/spellcheck.yml

@@ -0,0 +1,30 @@
+---
+name: 'Check spelling'
+on:
+  push:
+    branches: [main]
+  pull_request:
+    branches: [main]
+
+concurrency:
+  group: spellcheck-${{ github.ref }}
+  cancel-in-progress: true
+
+permissions:
+  contents: read
+
+jobs:
+  spellcheck:
+    runs-on: ubuntu-latest
+    if: ${{ github.actor != 'dependabot[bot]' }}
+    steps:
+      - uses: actions/checkout@de0fac2e4500dabe0009e67214ff5f5447ce83dd # v6.0.2
+        with:
+          persist-credentials: false
+
+      - uses: streetsidesoftware/cspell-action@9cd41bb518a24fefdafd9880cbab8f0ceba04d28 # v8.3.0
+        with:
+          check_dot_files: false
+          incremental_files_only: true
+          inline: warning
+          suggestions: true

.github/workflows/super-linter.yml

@@ -1,3 +1,4 @@
+---
 name: Lint Code Base
 
 on:

.htmlhintrc

@@ -19,6 +19,7 @@
   "id-unique": false,
   "inline-script-disabled": false,
   "inline-style-disabled": false,
+  "link-rel-canonical-require": true,
   "main-require": true,
   "meta-charset-require": true,
   "meta-description-require": true,

.nvmrc

@@ -0,0 +1 @@
+22.22.2

.prettierignore

@@ -0,0 +1 @@
+*.min.*

.vscode/extensions.json

@@ -0,0 +1,5 @@
+{
+  "recommendations": [
+    "EditorConfig.EditorConfig"
+  ]
+}

.vscode/settings.json

@@ -0,0 +1,9 @@
+{
+  "editor.codeActionsOnSave": {
+    "source.fixAll.eslint": "explicit",
+    "source.fixAll.stylelint": "always"
+  },
+  "editor.formatOnSave": true,
+  "editor.renderWhitespace": "all",
+  "eslint.validate": ["javascript"]
+}