chore: add knip to validate included dependencies

.knip.jsonc

@@ -0,0 +1,39 @@
+{
+  "$schema": "https://unpkg.com/knip@5/schema-jsonc.json",
+  "entry": [
+    "bin/mocha.js!",
+    "bin/_mocha!",
+    "browser-entry.js!",
+    "index.js!",
+    "lib/cli/index.js!",
+    ".eleventy.js",
+    "karma.conf.js"
+  ],
+  "project": [
+    "{bin,lib,scripts,test}/**/*.{js,ts,mjs,cjs}"
+  ],
+  "ignore": [
+    "test/integration/fixtures/esm/type-module/test-that-imports-non-existing-module.fixture.js",
+    "test/integration/fixtures/options/watch/test-with-dependency.fixture.js"
+  ],
+  "ignoreDependencies": [
+    "@mocha/docdash",
+    "coffeescript",
+    "fake",
+    "jsdoc-ts-utils",
+    "karma-chrome-launcher",
+    "karma-mocha-reporter",
+    "karma-mocha",
+    "karma-sauce-launcher",
+    "non-existent-package"
+  ],
+  "mocha": {
+    "entry": ["test/**/*.{js,ts,mjs,cjs}"]
+  },
+  "webpack": {
+    "config": "test/browser-specific/fixtures/webpack/webpack.config.js"
+  },
+  "rules": {
+    "exports": "off"
+  }
+}

lib/cli/commands.js

@@ -7,7 +7,8 @@
  * @module
  */
 
-exports.init = require('./init');
-
-// default command
-exports.run = require('./run');
+module.exports = {
+  init: require('./init'),
+  // default command
+  run: require('./run'),
+}

lib/cli/run.js

@@ -24,7 +24,7 @@ const {
 } = require('./run-helpers');
 const {ONE_AND_DONES, ONE_AND_DONE_ARGS} = require('./one-and-dones');
 const debug = require('debug')('mocha:cli:run');
-const defaults = require('../mocharc');
+const defaults = require('../mocharc.json');
 const {types, aliases} = require('./run-option-metadata');
 
 /**