chore: enabled ESLint's no-unused-vars (#5399)

Author: JoshuaKGoldberg

eslint.config.js

@@ -23,6 +23,7 @@ module.exports = [
     },
     rules: {
       'n/prefer-node-protocol': 'error',
+      'no-unused-vars': 'error',
       strict: ['error', 'global'],
 
       'no-var': 'off',

lib/cli/collect-files.js

@@ -1,6 +1,5 @@
 'use strict';
 
-const fs = require('node:fs');
 const path = require('node:path');
 const pc = require('picocolors');
 const debug = require('debug')('mocha:cli:run:helpers');

lib/cli/run-helpers.js

@@ -17,7 +17,6 @@ const {format} = require('node:util');
 const {createInvalidLegacyPluginError} = require('../errors');
 const {requireOrImport} = require('../nodejs/esm-utils');
 const PluginLoader = require('../plugin-loader');
-const {UnmatchedFile} = require('./collect-files');
 
 /**
  * Exits Mocha when tests + code under test has finished execution (default)

lib/errors.js

@@ -507,10 +507,9 @@ function createTimeoutError(msg, timeout, file) {
  * @public
  * @static
  * @param {string} message - Error message to be displayed.
- * @param {string} filename - File name
  * @returns {Error} Error with code {@link constants.UNPARSABLE_FILE}
  */
-function createUnparsableFileError(message, filename) {
+function createUnparsableFileError(message) {
   var err = new Error(message);
   err.code = constants.UNPARSABLE_FILE;
   return err;

lib/reporters/html.js

@@ -92,7 +92,6 @@ function HTML(runner, options) {
     items[progressIndex].getElementsByClassName('ring-flatlight')[0],
     items[progressIndex].getElementsByClassName('ring-highlight')[0]
   ];
-  var progressRingRadius = null; // computed CSS unavailable now, so set later
   var root = document.getElementById('mocha');
 
   if (!root) {

lib/reporters/tap.js

@@ -97,7 +97,7 @@ function title(test) {
  * @param {string} format - `printf`-like format string
  * @param {...*} [varArgs] - Format string arguments
  */
-function println(format, varArgs) {
+function println() {
   var vargs = Array.from(arguments);
   vargs[0] += '\n';
   process.stdout.write(sprintf.apply(null, vargs));
@@ -184,9 +184,8 @@ TAPProducer.prototype.writePending = function (n, test) {
  * @abstract
  * @param {number} n - Index of test that failed.
  * @param {Test} test - Instance containing test information.
- * @param {Error} err - Reason the test failed.
  */
-TAPProducer.prototype.writeFail = function (n, test, err) {
+TAPProducer.prototype.writeFail = function (n, test) {
   println('not ok %d %s', n, title(test));
 };
 

lib/runner.js

@@ -1166,7 +1166,7 @@ Runner.prototype.run = function (fn, opts = {}) {
  *   }
  * }
  */
-Runner.prototype.linkPartialObjects = function (value) {
+Runner.prototype.linkPartialObjects = function () {
   return this;
 };
 

lib/utils.js

@@ -543,7 +543,7 @@ exports.noop = function () {};
  * @param {...*} [obj] - Arguments to `Object.assign()`.
  * @returns {Object} An object with no prototype, having `...obj` properties
  */
-exports.createMap = function (obj) {
+exports.createMap = function () {
   return Object.assign.apply(
     null,
     [Object.create(null)].concat(Array.prototype.slice.call(arguments))

test/integration/hook-err.spec.js

@@ -292,7 +292,7 @@ function onlyConsoleOutput() {
   };
 }
 
-function onlyErrorTitle(line) {
+function onlyErrorTitle() {
   let foundErrorTitle = false;
   let foundError = false;
   return line => {

test/integration/options/posixExitCodes.spec.js

@@ -4,7 +4,6 @@ var helpers = require('../helpers');
 var runMocha = helpers.runMocha;
 var os = require('node:os');
 
-const EXIT_SUCCESS = 0;
 const EXIT_FAILURE = 1;
 const SIGNAL_OFFSET = 128;