chore: enable ESLint's recommended JS rules

docs/_data/supporters.js

@@ -139,6 +139,7 @@ const getAllOrders = async (slug = 'mochajs') => {
   const variables = {limit: GRAPHQL_PAGE_SIZE, offset: 0, slug};
 
   // Handling pagination if necessary (2 pages for ~1400 results in May 2019)
+  // eslint-disable-next-line no-constant-condition
   while (true) {
     const result = await needle(
       'post',

eslint.config.js

@@ -9,8 +9,8 @@ const messages = {
 };
 
 module.exports = [
+  js.configs.recommended,
   {
-    ...js.configs.recommended,
     languageOptions: {
       ecmaVersion: 2020,
       globals: {
@@ -20,6 +20,8 @@ module.exports = [
       sourceType: 'script'
     },
     rules: {
+      'no-empty': 'off',
+      'no-redeclare': 'off',
       'no-var': 'off',
       strict: ['error', 'global']
     }

lib/cli/collect-files.js

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

lib/cli/run-helpers.js

@@ -17,7 +17,6 @@ const {format} = require('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

@@ -94,10 +94,9 @@ function title(test) {
  * Writes newline-terminated formatted string to reporter output stream.
  *
  * @private
- * @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 +183,8 @@ 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

@@ -1148,7 +1148,6 @@ Runner.prototype.run = function (fn, opts = {}) {
  * unique ID's. Does nothing in serial mode, because the object references already exist.
  * Subclasses can implement this (e.g., `ParallelBufferedRunner`)
  * @abstract
- * @param {boolean} [value] - If `true`, enable partial object linking, otherwise disable
  * @returns {Runner}
  * @chainable
  * @public
@@ -1166,7 +1165,7 @@ 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/init.spec.js

@@ -13,14 +13,14 @@ describe('init command', function () {
     tmpdir = path.join(os.tmpdir(), 'mocha-init');
     try {
       fs.mkdirSync(tmpdir);
-    } catch (ignored) {}
+    } catch {}
     expect(fs.existsSync(tmpdir), 'to be true');
   });
 
   afterEach(function () {
     try {
       rimraf.sync(tmpdir);
-    } catch (ignored) {}
+    } catch {}
   });
 
   describe('when no path is supplied', function () {

test/integration/options/parallel.spec.js

@@ -510,7 +510,7 @@ describe('--parallel', function () {
               let pids = null;
               try {
                 pids = await pidtree(childPid, {root: true});
-              } catch (ignored) {}
+              } catch {}
               return pids;
             })
           ),
@@ -536,7 +536,7 @@ describe('--parallel', function () {
               let pids = null;
               try {
                 pids = await pidtree(childPid, {root: true});
-              } catch (ignored) {}
+              } catch {}
               return pids;
             })
           ),

test/integration/reporters.spec.js

@@ -49,7 +49,7 @@ describe('reporters', function () {
         '</testsuite>'
       ];
 
-      run('passing.fixture.js', args, function (err, result) {
+      run('passing.fixture.js', args, function (err) {
         if (err) return done(err);
 
         var xml = fs.readFileSync(tmpFile, 'utf8');

test/node-unit/cli/options.spec.js

@@ -344,14 +344,14 @@ describe('options', function () {
           it('should not look for a config', function () {
             try {
               loadOptions(`--config ${config}`);
-            } catch (ignored) {}
+            } catch {}
             expect(findConfig, 'was not called');
           });
 
           it('should attempt to load file at path', function () {
             try {
               loadOptions(`--config ${config}`);
-            } catch (ignored) {}
+            } catch {}
             expect(loadConfig, 'to have a call satisfying', [config]);
           });
 

test/reporters/base.spec.js

@@ -37,7 +37,7 @@ describe('Base reporter', function () {
     return diffStr;
   }
 
-  var gather = function (chunk, encoding, cb) {
+  var gather = function (chunk) {
     stdout.push(chunk);
   };
 
@@ -524,14 +524,14 @@ describe('Base reporter', function () {
       var err1 = {
         message: 'Error',
         stack: 'Error\nfoo\nbar',
-        showDiff: false,
+        showDiff: false
       };
       var err2 = {
         message: 'Cause1',
         stack: 'Cause1\nbar\nfoo',
         showDiff: false,
         cause: err1
-      }
+      };
       err1.cause = err2;
 
       var test = makeTest(err1);
@@ -552,7 +552,7 @@ describe('Base reporter', function () {
         stack: 'Error\nfoo\nbar',
         showDiff: false,
         cause: {
-          showDiff: false,
+          showDiff: false
         }
       };
 

test/reporters/helpers.js

@@ -165,8 +165,7 @@ function makeExpectedTest(
   expectedFullTitle,
   expectedFile,
   expectedDuration,
-  currentRetry,
-  expectedBody
+  currentRetry
 ) {
   return {
     title: expectedTitle,
@@ -203,7 +202,7 @@ function createRunReporterFunction(ctor) {
     var stdoutWriteStub = sinon.stub(process.stdout, 'write');
     var stdout = [];
 
-    var gather = function (chunk, enc, callback) {
+    var gather = function (chunk) {
       stdout.push(chunk);
       if (tee) {
         origStdoutWrite.call(process.stdout, chunk);

test/reporters/nyan.spec.js

@@ -161,7 +161,7 @@ describe('Nyan reporter', function () {
 
     beforeEach(function () {
       stdoutWriteStub = sinon.stub(process.stdout, 'write');
-      stdoutWriteStub.callsFake(function (chunk, encoding, cb) {
+      stdoutWriteStub.callsFake(function (chunk) {
         stdout.push(chunk);
       });
       stdout = [];
@@ -260,7 +260,7 @@ describe('Nyan reporter', function () {
 
     beforeEach(function () {
       stdoutWriteStub = sinon.stub(process.stdout, 'write');
-      stdoutWriteStub.callsFake(function (chunk, encoding, cb) {
+      stdoutWriteStub.callsFake(function (chunk) {
         stdout.push(chunk);
       });
       stdout = [];
@@ -289,7 +289,7 @@ describe('Nyan reporter', function () {
 
     beforeEach(function () {
       stdoutWriteStub = sinon.stub(process.stdout, 'write');
-      stdoutWriteStub.callsFake(function (chunk, encoding, cb) {
+      stdoutWriteStub.callsFake(function (chunk) {
         stdout.push(chunk);
       });
       stdout = [];
@@ -452,7 +452,7 @@ describe('Nyan reporter', function () {
         return type + n;
       });
       var stdoutWriteStub = sinon.stub(process.stdout, 'write');
-      stdoutWriteStub.callsFake(function (chunk, encoding, cb) {
+      stdoutWriteStub.callsFake(function (chunk) {
         stdout.push(chunk);
       });
       stdout = [];
@@ -521,7 +521,7 @@ describe('Nyan reporter', function () {
 
     beforeEach(function () {
       var stdoutWriteStub = sinon.stub(process.stdout, 'write');
-      stdoutWriteStub.callsFake(function (chunk, encoding, cb) {
+      stdoutWriteStub.callsFake(function (chunk) {
         stdout.push(chunk);
       });
       stdout = [];

test/reporters/xunit.spec.js

@@ -225,7 +225,7 @@ describe('XUnit reporter', function () {
               }
               cb();
             }),
-            write: function (chunk, encoding, cb) {}
+            write: function () {}
           }
         };
       });
@@ -544,7 +544,7 @@ describe('XUnit reporter', function () {
 
     before(function () {
       fileStream = {
-        write: function (chunk, encoding, cb) {
+        write: function (chunk) {
           lines.push(chunk);
         }
       };

test/unit/runnable.spec.js

@@ -173,7 +173,9 @@ describe('Runnable(title, fn)', function () {
     var run;
 
     beforeEach(function () {
-      run = new Runnable('foo', function (done) {});
+      run = new Runnable('foo', function (done) {
+        done();
+      });
     });
 
     it('should be .async', function () {
@@ -387,7 +389,7 @@ describe('Runnable(title, fn)', function () {
         });
 
         it('should not throw its own exception if passed a non-object', function (done) {
-          var runnable = new Runnable('foo', function (done) {
+          var runnable = new Runnable('foo', function () {
             /* eslint no-throw-literal: off */
             throw null;
           });
@@ -401,7 +403,7 @@ describe('Runnable(title, fn)', function () {
 
       describe('when an exception is thrown and is allowed to remain uncaught', function () {
         it('throws an error when it is allowed', function (done) {
-          var runnable = new Runnable('foo', function (done) {
+          var runnable = new Runnable('foo', function () {
             throw new Error('fail');
           });
           runnable.allowUncaught = true;
@@ -466,8 +468,13 @@ describe('Runnable(title, fn)', function () {
       it('should allow updating the timeout', function (done) {
         var spy = sinon.spy();
         var runnable = new Runnable('foo', function (done) {
-          setTimeout(spy, 1);
-          setTimeout(spy, 100);
+          setTimeout(function () {
+            spy();
+            setTimeout(function () {
+              spy();
+              done();
+            }, 50);
+          }, 10);
         });
         runnable.timeout(50);
         runnable.run(function (err) {
@@ -509,7 +516,7 @@ describe('Runnable(title, fn)', function () {
 
       describe('when the promise is fulfilled with a value', function () {
         var fulfilledPromise = {
-          then: function (fulfilled, rejected) {
+          then: function (fulfilled) {
             setTimeout(function () {
               fulfilled({});
             });
@@ -626,6 +633,7 @@ describe('Runnable(title, fn)', function () {
         var runnable = new Runnable('foo', function (done) {
           // normally "this" but it gets around having to muck with a context
           runnable.skip();
+          done();
         });
         runnable.run(function (err) {
           expect(err, 'to be undefined');
@@ -641,6 +649,7 @@ describe('Runnable(title, fn)', function () {
           runnable.skip();
           /* istanbul ignore next */
           aborted = false;
+          done();
         });
         runnable.run(function () {
           process.nextTick(function () {

test/unit/runner.spec.js

@@ -879,7 +879,7 @@ describe('Runner', function () {
       it('async - should allow unhandled errors in hooks to propagate through', function (done) {
         // the `done` argument, although unused, it triggers the async path
         // see this.async in the Runnable constructor
-        suite.beforeEach(function (done) {
+        suite.beforeEach(function () {
           throw new Error('allow unhandled errors in async hooks');
         });
         var runner = new Runner(suite);
@@ -1045,7 +1045,7 @@ describe('Runner', function () {
                   function () {
                     try {
                       runner.uncaught(err);
-                    } catch (ignored) {}
+                    } catch {}
                   },
                   'not to emit from',
                   runner,