tj · Mar 16, 2020 · Mar 16, 2020 · Mar 16, 2020 · Mar 16, 2020 · Mar 23, 2020
diff --git a/.github/workflows/tests.yml b/.github/workflows/tests.yml
@@ -9,7 +9,7 @@ jobs:
     strategy:
       fail-fast: false
       matrix:
-        node-version: [8.x, 10.x, 12.x]
+        node-version: [8.x, 10.x, 12.x, 14.x]
         os: [ubuntu-latest, windows-latest, macos-latest]
 
     steps:

diff --git a/CHANGELOG.md b/CHANGELOG.md
@@ -7,6 +7,27 @@ and this project adheres to [Semantic Versioning](http://semver.org/spec/v2.0.0.
 
 <!-- markdownlint-disable MD024 -->
 
+## [5.1.0] (2020-04-25)
+
+### Added
+
+- support for multiple command aliases, the first of which is shown in the auto-generated help ([#531], [#1236])
+- configuration support in `addCommand()` for `hidden` and `isDefault` ([#1232])
+
+### Fixed
+
+- omit masked help flags from the displayed help ([#645], [#1247])
+- remove old short help flag when change help flags using `helpOption` ([#1248])
+
+### Changed
+
+- remove use of `arguments` to improve auto-generated help in editors ([#1235])
+- rename `.command()` configuration `noHelp` to `hidden` (but not remove old support) ([#1232])
+- improvements to documentation
+- update dependencies
+- update tested versions of node
+- eliminate lint errors in TypeScript ([#1208])
+
 ## [5.0.0] (2020-03-14)
 
 ### Added
@@ -274,8 +295,10 @@ program
 [#432]: https://github.com/tj/commander.js/issues/432
 [#508]: https://github.com/tj/commander.js/issues/508
 [#512]: https://github.com/tj/commander.js/issues/512
+[#531]: https://github.com/tj/commander.js/issues/531
 [#599]: https://github.com/tj/commander.js/issues/599
 [#611]: https://github.com/tj/commander.js/issues/611
+[#645]: https://github.com/tj/commander.js/issues/645
 [#697]: https://github.com/tj/commander.js/issues/697
 [#742]: https://github.com/tj/commander.js/issues/742
 [#764]: https://github.com/tj/commander.js/issues/764
@@ -335,8 +358,15 @@ program
 [#1184]: https://github.com/tj/commander.js/pull/1184
 [#1191]: https://github.com/tj/commander.js/pull/1191
 [#1195]: https://github.com/tj/commander.js/pull/1195
+[#1208]: https://github.com/tj/commander.js/pull/1208
+[#1232]: https://github.com/tj/commander.js/pull/1232
+[#1235]: https://github.com/tj/commander.js/pull/1235
+[#1236]: https://github.com/tj/commander.js/pull/1236
+[#1247]: https://github.com/tj/commander.js/pull/1247
+[#1248]: https://github.com/tj/commander.js/pull/1248
 
 [Unreleased]: https://github.com/tj/commander.js/compare/master...develop
+[5.1.0]: https://github.com/tj/commander.js/compare/v5.0.0..v5.1.0
 [5.0.0]: https://github.com/tj/commander.js/compare/v4.1.1..v5.0.0
 [5.0.0-4]: https://github.com/tj/commander.js/compare/v5.0.0-3..v5.0.0-4
 [5.0.0-3]: https://github.com/tj/commander.js/compare/v5.0.0-2..v5.0.0-3

diff --git a/Readme.md b/Readme.md
@@ -300,7 +300,7 @@ program.version('0.0.1', '-v, --vers', 'output the current version');
 
 ## Commands
 
-You can specify (sub)commands for your top-level command using `.command()` or `.addCommand()`. There are two ways these can be implemented: using an action handler attached to the command, or as a stand-alone executable file (described in more detail later). The subcommands may be nested ([example](./examples/nestedCommands.js)).
+You can specify (sub)commands using `.command()` or `.addCommand()`. There are two ways these can be implemented: using an action handler attached to the command, or as a stand-alone executable file (described in more detail later). The subcommands may be nested ([example](./examples/nestedCommands.js)).
 
 In the first parameter to `.command()` you specify the command name and any command arguments. The arguments may be `<required>` or `[optional]`, and the last argument may also be `variadic...`.
 
@@ -319,22 +319,22 @@ program
   });
 
 // Command implemented using stand-alone executable file (description is second parameter to `.command`)
-// Returns top-level command for adding more commands.
+// Returns `this` for adding more commands.
 program
   .command('start <service>', 'start named service')
   .command('stop [service]', 'stop named service, or all if no name supplied');
 
 // Command prepared separately.
-// Returns top-level command for adding more commands.
+// Returns `this` for adding more commands.
 program
   .addCommand(build.makeBuildCommand());
 ```
 
-Configuration options can be passed with the call to `.command()`. Specifying `true` for `opts.noHelp` will remove the command from the generated help output. Specifying `true` for `opts.isDefault` will run the subcommand if no other subcommand is specified ([example](./examples/defaultCommand.js)).
+Configuration options can be passed with the call to `.command()` and `.addCommand()`. Specifying `true` for `opts.hidden` will remove the command from the generated help output. Specifying `true` for `opts.isDefault` will run the subcommand if no other subcommand is specified ([example](./examples/defaultCommand.js)).
 
 ### Specify the argument syntax
 
-You use `.arguments` to specify the arguments for the top-level command, and for subcommands they are included in the `.command` call. Angled brackets (e.g. `<required>`) indicate required input. Square brackets (e.g. `[optional]`) indicate optional input.
+You use `.arguments` to specify the arguments for the top-level command, and for subcommands they are usually included in the `.command` call. Angled brackets (e.g. `<required>`) indicate required input. Square brackets (e.g. `[optional]`) indicate optional input.
 
 ```js
 const { program } = require('commander');

diff --git a/SECURITY.md b/SECURITY.md
@@ -6,7 +6,8 @@ Old versions receive security updates for six months.
 
 | Version | Supported                                  |
 | ------- | ------------------------------------------ |
-| 4.x     | :white_check_mark:                         |
+| 5.x     | :white_check_mark:                         |
+| 4.x     | :white_check_mark: support ends 2020-09-14 |
 | 3.x     | :white_check_mark: support ends 2020-05-01 |
 | < 3     | :x:                                        |
 

diff --git a/examples/nestedCommands.js b/examples/nestedCommands.js
@@ -4,7 +4,7 @@ const program = new commander.Command();
 
 // Commander supports nested subcommands.
 // .command() can add a subcommand with an action handler or an executable.
-// .addCommand() adds a prepared command with an actiomn handler.
+// .addCommand() adds a prepared command with an action handler.
 
 // Example output:
 //
@@ -21,9 +21,9 @@ brew
     console.log('brew tea');
   });
 brew
-  .command('tea')
+  .command('coffee')
   .action(() => {
-    console.log('brew tea');
+    console.log('brew coffee');
   });
 
 // Add nested commands using `.addCommand().

diff --git a/index.js b/index.js
@@ -117,9 +117,9 @@ class Command extends EventEmitter {
     this._executableFile = null; // custom name for executable
     this._defaultCommandName = null;
     this._exitCallback = null;
-    this._alias = null;
+    this._aliases = [];
 
-    this._noHelp = false;
+    this._hidden = false;
     this._helpFlags = '-h, --help';
     this._helpDescription = 'display help for command';
     this._helpShortFlag = '-h';
@@ -153,7 +153,7 @@ class Command extends EventEmitter {
    * @param {string} nameAndArgs - command name and arguments, args are `<required>` or `[optional]` and last may also be `variadic...`
    * @param {Object|string} [actionOptsOrExecDesc] - configuration options (for action), or description (for executable)
    * @param {Object} [execOpts] - configuration options (for executable)
-   * @return {Command} returns new command for action handler, or top-level command for executable command
+   * @return {Command} returns new command for action handler, or `this` for executable command
    * @api public
    */
 
@@ -174,7 +174,7 @@ class Command extends EventEmitter {
     }
     if (opts.isDefault) this._defaultCommandName = cmd._name;
 
-    cmd._noHelp = !!opts.noHelp;
+    cmd._hidden = !!(opts.noHelp || opts.hidden);
     cmd._helpFlags = this._helpFlags;
     cmd._helpDescription = this._helpDescription;
     cmd._helpShortFlag = this._helpShortFlag;
@@ -216,11 +216,12 @@ class Command extends EventEmitter {
    * See .command() for creating an attached subcommand which inherits settings from its parent.
    *
    * @param {Command} cmd - new subcommand
-   * @return {Command} parent command for chaining
+   * @param {Object} [opts] - configuration options
+   * @return {Command} `this` command for chaining
    * @api public
    */
 
-  addCommand(cmd) {
+  addCommand(cmd, opts) {
     if (!cmd._name) throw new Error('Command passed to .addCommand() must have a name');
 
     // To keep things simple, block automatic name generation for deeply nested executables.
@@ -235,13 +236,17 @@ class Command extends EventEmitter {
     }
     checkExplicitNames(cmd.commands);
 
+    opts = opts || {};
+    if (opts.isDefault) this._defaultCommandName = cmd._name;
+    if (opts.noHelp || opts.hidden) cmd._hidden = true; // modifying passed command due to existing implementation
+
     this.commands.push(cmd);
     cmd.parent = this;
     return this;
   };
 
   /**
-   * Define argument syntax for the top-level command.
+   * Define argument syntax for the command.
    *
    * @api public
    */
@@ -257,7 +262,7 @@ class Command extends EventEmitter {
    *    addHelpCommand(false); // force off
    *    addHelpCommand('help [cmd]', 'display help for [cmd]'); // force on with custom detais
    *
-   * @return {Command} for chaining
+   * @return {Command} `this` command for chaining
    * @api public
    */
 
@@ -293,7 +298,7 @@ class Command extends EventEmitter {
    * For example `["[type]"]` becomes `[{ required: false, name: 'type' }]`.
    *
    * @param {Array} args
-   * @return {Command} for chaining
+   * @return {Command} `this` command for chaining
    * @api private
    */
 
@@ -336,7 +341,7 @@ class Command extends EventEmitter {
    * Register callback to use as replacement for calling process.exit.
    *
    * @param {Function} [fn] optional callback which will be passed a CommanderError, defaults to throwing
-   * @return {Command} for chaining
+   * @return {Command} `this` command for chaining
    * @api public
    */
 
@@ -386,7 +391,7 @@ class Command extends EventEmitter {
    *        });
    *
    * @param {Function} fn
-   * @return {Command} for chaining
+   * @return {Command} `this` command for chaining
    * @api public
    */
 
@@ -425,7 +430,7 @@ class Command extends EventEmitter {
    * @param {string} description
    * @param {Function|*} [fn] - custom option processing function or default vaue
    * @param {*} [defaultValue]
-   * @return {Command} for chaining
+   * @return {Command} `this` command for chaining
    * @api private
    */
 
@@ -543,7 +548,7 @@ class Command extends EventEmitter {
    * @param {string} description
    * @param {Function|*} [fn] - custom option processing function or default vaue
    * @param {*} [defaultValue]
-   * @return {Command} for chaining
+   * @return {Command} `this` command for chaining
    * @api public
    */
 
@@ -561,7 +566,7 @@ class Command extends EventEmitter {
   * @param {string} description
   * @param {Function|*} [fn] - custom option processing function or default vaue
   * @param {*} [defaultValue]
-  * @return {Command} for chaining
+  * @return {Command} `this` command for chaining
   * @api public
   */
 
@@ -577,7 +582,7 @@ class Command extends EventEmitter {
    * @api public
    */
   allowUnknownOption(arg) {
-    this._allowUnknownOption = arguments.length === 0 || arg;
+    this._allowUnknownOption = (arg === undefined) || arg;
     return this;
   };
 
@@ -586,7 +591,7 @@ class Command extends EventEmitter {
     * or store separately (specify false). In both cases the option values can be accessed using .opts().
     *
     * @param {boolean} value
-    * @return {Command} Command for chaining
+    * @return {Command} `this` command for chaining
     * @api public
     */
 
@@ -603,7 +608,7 @@ class Command extends EventEmitter {
     * or just the options (specify false).
     *
     * @param {boolean} value
-    * @return {Command} Command for chaining
+    * @return {Command} `this` command for chaining
     * @api public
     */
 
@@ -658,7 +663,7 @@ class Command extends EventEmitter {
    * @param {string[]} [argv] - optional, defaults to process.argv
    * @param {Object} [parseOptions] - optionally specify style of options with from: node/user/electron
    * @param {string} [parseOptions.from] - where the args are from: 'node', 'user', 'electron'
-   * @return {Command} for chaining
+   * @return {Command} `this` command for chaining
    * @api public
    */
 
@@ -932,7 +937,7 @@ class Command extends EventEmitter {
    */
   _findCommand(name) {
     if (!name) return undefined;
-    return this.commands.find(cmd => cmd._name === name || cmd._alias === name);
+    return this.commands.find(cmd => cmd._name === name || cmd._aliases.includes(name));
   };
 
   /**
@@ -1172,12 +1177,12 @@ class Command extends EventEmitter {
    * @param {string} str
    * @param {string} [flags]
    * @param {string} [description]
-   * @return {Command | string} this for chaining
+   * @return {this | string} `this` command for chaining, or version string if no arguments
    * @api public
    */
 
   version(str, flags, description) {
-    if (arguments.length === 0) return this._version;
+    if (str === undefined) return this._version;
     this._version = str;
     flags = flags || '-V, --version';
     description = description || 'output the version number';
@@ -1196,36 +1201,57 @@ class Command extends EventEmitter {
    *
    * @param {string} str
    * @param {Object} [argsDescription]
-   * @return {String|Command}
+   * @return {string|Command}
    * @api public
    */
 
   description(str, argsDescription) {
-    if (arguments.length === 0) return this._description;
+    if (str === undefined && argsDescription === undefined) return this._description;
     this._description = str;
     this._argsDescription = argsDescription;
     return this;
   };
 
   /**
-   * Set an alias for the command
+   * Set an alias for the command.
    *
-   * @param {string} alias
-   * @return {String|Command}
+   * You may call more than once to add multiple aliases. Only the first alias is shown in the auto-generated help.
+   *
+   * @param {string} [alias]
+   * @return {string|Command}
    * @api public
    */
 
   alias(alias) {
+    if (alias === undefined) return this._aliases[0]; // just return first, for backwards compatibility
+
     let command = this;
-    if (this.commands.length !== 0) {
+    if (this.commands.length !== 0 && this.commands[this.commands.length - 1]._executableHandler) {
+      // assume adding alias for last added executable subcommand, rather than this
       command = this.commands[this.commands.length - 1];
     }
 
-    if (arguments.length === 0) return command._alias;
-
     if (alias === command._name) throw new Error('Command alias can\'t be the same as its name');
 
-    command._alias = alias;
+    command._aliases.push(alias);
+    return this;
+  };
+
+  /**
+   * Set aliases for the command.
+   *
+   * Only the first alias is shown in the auto-generated help.
+   *
+   * @param {string[]} [aliases]
+   * @return {string[]|Command}
+   * @api public
+   */
+
+  aliases(aliases) {
+    // Getter for the array of aliases is the main reason for having aliases() in addition to alias().
+    if (aliases === undefined) return this._aliases;
+
+    aliases.forEach((alias) => this.alias(alias));
     return this;
   };
 
@@ -1238,17 +1264,18 @@ class Command extends EventEmitter {
    */
 
   usage(str) {
-    const args = this._args.map((arg) => {
-      return humanReadableArgName(arg);
-    });
+    if (str === undefined) {
+      if (this._usage) return this._usage;
 
-    const usage = '[options]' +
-      (this.commands.length ? ' [command]' : '') +
-      (this._args.length ? ' ' + args.join(' ') : '');
+      const args = this._args.map((arg) => {
+        return humanReadableArgName(arg);
+      });
+      return '[options]' +
+        (this.commands.length ? ' [command]' : '') +
+        (this._args.length ? ' ' + args.join(' ') : '');
+    }
 
-    if (arguments.length === 0) return this._usage || usage;
     this._usage = str;
-
     return this;
   };
 
@@ -1261,7 +1288,7 @@ class Command extends EventEmitter {
    */
 
   name(str) {
-    if (arguments.length === 0) return this._name;
+    if (str === undefined) return this._name;
     this._name = str;
     return this;
   };
@@ -1275,15 +1302,15 @@ class Command extends EventEmitter {
 
   prepareCommands() {
     const commandDetails = this.commands.filter((cmd) => {
-      return !cmd._noHelp;
+      return !cmd._hidden;
     }).map((cmd) => {
       const args = cmd._args.map((arg) => {
         return humanReadableArgName(arg);
       }).join(' ');
 
       return [
         cmd._name +
-          (cmd._alias ? '|' + cmd._alias : '') +
+          (cmd._aliases[0] ? '|' + cmd._aliases[0] : '') +
           (cmd.options.length ? ' [options]' : '') +
           (args ? ' ' + args : ''),
         cmd._description
@@ -1374,17 +1401,33 @@ class Command extends EventEmitter {
 
   optionHelp() {
     const width = this.padWidth();
-
     const columns = process.stdout.columns || 80;
     const descriptionWidth = columns - width - 4;
+    function padOptionDetails(flags, description) {
+      return pad(flags, width) + '  ' + optionalWrap(description, descriptionWidth, width + 2);
+    };
 
-    // Append the help information
-    return this.options.map((option) => {
+    // Explicit options (including version)
+    const help = this.options.map((option) => {
       const fullDesc = option.description +
         ((!option.negate && option.defaultValue !== undefined) ? ' (default: ' + JSON.stringify(option.defaultValue) + ')' : '');
-      return pad(option.flags, width) + '  ' + optionalWrap(fullDesc, descriptionWidth, width + 2);
-    }).concat([pad(this._helpFlags, width) + '  ' + optionalWrap(this._helpDescription, descriptionWidth, width + 2)])
-      .join('\n');
+      return padOptionDetails(option.flags, fullDesc);
+    });
+
+    // Implicit help
+    const showShortHelpFlag = this._helpShortFlag && !this._findOption(this._helpShortFlag);
+    const showLongHelpFlag = !this._findOption(this._helpLongFlag);
+    if (showShortHelpFlag || showLongHelpFlag) {
+      let helpFlags = this._helpFlags;
+      if (!showShortHelpFlag) {
+        helpFlags = this._helpLongFlag;
+      } else if (!showLongHelpFlag) {
+        helpFlags = this._helpShortFlag;
+      }
+      help.push(padOptionDetails(helpFlags, this._helpDescription));
+    }
+
+    return help.join('\n');
   };
 
   /**
@@ -1443,8 +1486,8 @@ class Command extends EventEmitter {
     }
 
     let cmdName = this._name;
-    if (this._alias) {
-      cmdName = cmdName + '|' + this._alias;
+    if (this._aliases[0]) {
+      cmdName = cmdName + '|' + this._aliases[0];
     }
     let parentCmdNames = '';
     for (let parentCmd = this.parent; parentCmd; parentCmd = parentCmd.parent) {
@@ -1501,7 +1544,7 @@ class Command extends EventEmitter {
    *
    * @param {string} [flags]
    * @param {string} [description]
-   * @return {Command}
+   * @return {Command} `this` command for chaining
    * @api public
    */
 
@@ -1511,6 +1554,7 @@ class Command extends EventEmitter {
 
     const splitFlags = this._helpFlags.split(/[ ,|]+/);
 
+    this._helpShortFlag = undefined;
     if (splitFlags.length > 1) this._helpShortFlag = splitFlags.shift();
 
     this._helpLongFlag = splitFlags.shift();

diff --git a/package-lock.json b/package-lock.json
diff --git a/package.json b/package.json
@@ -1,6 +1,6 @@
 {
   "name": "commander",
-  "version": "5.0.0",
+  "version": "5.1.0",
   "description": "the complete solution for node.js command-line programs",
   "keywords": [
     "commander",
@@ -31,14 +31,14 @@
   ],
   "dependencies": {},
   "devDependencies": {
-    "@types/jest": "^25.1.4",
-    "@types/node": "^12.12.26",
-    "@typescript-eslint/eslint-plugin": "^2.23.0",
+    "@types/jest": "^25.2.1",
+    "@types/node": "^12.12.36",
+    "@typescript-eslint/eslint-plugin": "^2.29.0",
     "eslint": "^6.8.0",
-    "eslint-config-standard-with-typescript": "^14.0.0",
+    "eslint-config-standard-with-typescript": "^15.0.1",
     "eslint-plugin-jest": "^23.8.2",
-    "jest": "^25.1.0",
-    "standard": "^14.3.1",
+    "jest": "^25.4.0",
+    "standard": "^14.3.3",
     "typescript": "^3.7.5"
   },
   "typings": "typings/index.d.ts",

diff --git a/tests/command.alias.test.js b/tests/command.alias.test.js
@@ -12,11 +12,64 @@ test('when command has alias then appears in help', () => {
   expect(helpInformation).toMatch('info|i');
 });
 
-test('when command = alias then error', () => {
+test('when command has aliases added separately then only first appears in help', () => {
+  const program = new commander.Command();
+  program
+    .command('list [thing]')
+    .alias('ls')
+    .alias('dir');
+  const helpInformation = program.helpInformation();
+  expect(helpInformation).toMatch('list|ls ');
+});
+
+test('when command has aliases then only first appears in help', () => {
+  const program = new commander.Command();
+  program
+    .command('list [thing]')
+    .aliases(['ls', 'dir']);
+  const helpInformation = program.helpInformation();
+  expect(helpInformation).toMatch('list|ls ');
+});
+
+test('when command name = alias then error', () => {
   const program = new commander.Command();
   expect(() => {
     program
       .command('fail')
       .alias('fail');
   }).toThrow("Command alias can't be the same as its name");
 });
+
+test('when use alias then action handler called', () => {
+  const program = new commander.Command();
+  const actionMock = jest.fn();
+  program
+    .command('list')
+    .alias('ls')
+    .action(actionMock);
+  program.parse(['ls'], { from: 'user' });
+  expect(actionMock).toHaveBeenCalled();
+});
+
+test('when use second alias added separately then action handler called', () => {
+  const program = new commander.Command();
+  const actionMock = jest.fn();
+  program
+    .command('list')
+    .alias('ls')
+    .alias('dir')
+    .action(actionMock);
+  program.parse(['dir'], { from: 'user' });
+  expect(actionMock).toHaveBeenCalled();
+});
+
+test('when use second of aliases then action handler called', () => {
+  const program = new commander.Command();
+  const actionMock = jest.fn();
+  program
+    .command('list')
+    .aliases(['ls', 'dir'])
+    .action(actionMock);
+  program.parse(['dir'], { from: 'user' });
+  expect(actionMock).toHaveBeenCalled();
+});
diff --git a/tests/command.default.test.js b/tests/command.default.test.js
@@ -44,13 +44,47 @@ describe('default action command', () => {
     expect(actionMock).toHaveBeenCalled();
   });
 
-  test('when default subcommand and unrecognised argument then call default with argument', () => {
+  test('when default subcommand and unrecognised argument then call default', () => {
     const { program, actionMock } = makeProgram();
     program.parse('node test.js an-argument'.split(' '));
     expect(actionMock).toHaveBeenCalled();
   });
 
-  test('when default subcommand and unrecognised option then call default with option', () => {
+  test('when default subcommand and unrecognised option then call default', () => {
+    const { program, actionMock } = makeProgram();
+    program.parse('node test.js --an-option'.split(' '));
+    expect(actionMock).toHaveBeenCalled();
+  });
+});
+
+describe('default added command', () => {
+  function makeProgram() {
+    const actionMock = jest.fn();
+    const defaultCmd = new commander.Command('default')
+      .allowUnknownOption()
+      .action(actionMock);
+
+    const program = new commander.Command();
+    program
+      .command('other');
+    program
+      .addCommand(defaultCmd, { isDefault: true });
+    return { program, actionMock };
+  }
+
+  test('when default subcommand and no command then call default', () => {
+    const { program, actionMock } = makeProgram();
+    program.parse('node test.js'.split(' '));
+    expect(actionMock).toHaveBeenCalled();
+  });
+
+  test('when default subcommand and unrecognised argument then call default', () => {
+    const { program, actionMock } = makeProgram();
+    program.parse('node test.js an-argument'.split(' '));
+    expect(actionMock).toHaveBeenCalled();
+  });
+
+  test('when default subcommand and unrecognised option then call default', () => {
     const { program, actionMock } = makeProgram();
     program.parse('node test.js --an-option'.split(' '));
     expect(actionMock).toHaveBeenCalled();

diff --git a/tests/command.help.test.js b/tests/command.help.test.js
@@ -88,10 +88,45 @@ test('when call outputHelp(cb) then display cb output', () => {
   writeSpy.mockClear();
 });
 
+// noHelp is now named hidden, not officially deprecated yet
 test('when command sets noHelp then not displayed in helpInformation', () => {
   const program = new commander.Command();
   program
     .command('secret', 'secret description', { noHelp: true });
   const helpInformation = program.helpInformation();
   expect(helpInformation).not.toMatch('secret');
 });
+
+test('when command sets hidden then not displayed in helpInformation', () => {
+  const program = new commander.Command();
+  program
+    .command('secret', 'secret description', { hidden: true });
+  const helpInformation = program.helpInformation();
+  expect(helpInformation).not.toMatch('secret');
+});
+
+test('when addCommand with hidden:true then not displayed in helpInformation', () => {
+  const secretCmd = new commander.Command('secret');
+
+  const program = new commander.Command();
+  program
+    .addCommand(secretCmd, { hidden: true });
+  const helpInformation = program.helpInformation();
+  expect(helpInformation).not.toMatch('secret');
+});
+
+test('when help short flag masked then not displayed in helpInformation', () => {
+  const program = new commander.Command();
+  program
+    .option('-h, --host', 'select host');
+  const helpInformation = program.helpInformation();
+  expect(helpInformation).not.toMatch(/\W-h\W.*display help/);
+});
+
+test('when both help flags masked then not displayed in helpInformation', () => {
+  const program = new commander.Command();
+  program
+    .option('-h, --help', 'custom');
+  const helpInformation = program.helpInformation();
+  expect(helpInformation).not.toMatch('display help');
+});
diff --git a/tests/fixtures/pm b/tests/fixtures/pm
@@ -11,7 +11,7 @@ program
   .command('list', 'list packages installed').alias('lst')
   .command('listen', 'listen for supported signal events').alias('l')
   .command('publish', 'publish or update package').alias('p')
-  .command('default', 'default command', { noHelp: true, isDefault: true })
+  .command('default', 'default command', { hidden: true, isDefault: true })
   .command('specifyInstall', 'specify install subcommand', { executableFile: 'pm-install' })
   .command('specifyPublish', 'specify publish subcommand', { executableFile: 'pm-publish' })
   .command('silent', 'silently succeed')

diff --git a/typings/commander-tests.ts b/typings/commander-tests.ts
@@ -1,11 +1,16 @@
 import * as commander from './index';
-import { Script } from 'vm';
 
 // Test Commander usage with TypeScript.
 // This is NOT a usable program, just used to test for compile errors!
 
+// We declare lots of variables just to check types of right-side of expression, so disable this:
+/* eslint-disable @typescript-eslint/no-unused-vars */
+
+// This conflicts with esline rule saying no space!
+/* eslint-disable @typescript-eslint/space-before-function-paren */
+
 // Defined stricter type, as the options as properties `[key: string]: any`
-// makes the type checking very weak. 
+// makes the type checking very weak.
 // https://github.com/Microsoft/TypeScript/issues/25987#issuecomment-441224690
 type KnownKeys<T> = {
   [K in keyof T]: string extends K ? never : number extends K ? never : K
@@ -28,6 +33,7 @@ const errorInstance = new commander.CommanderError(1, 'code', 'message');
 
 // Command properties
 console.log(programWithOptions.someOption);
+// eslint-disable-next-line dot-notation
 console.log(programWithOptions['someOption']);
 const theArgs = program.args;
 const theCommands: commander.Command[] = program.commands;
@@ -39,22 +45,22 @@ const versionThis3: commander.Command = program.version('1.2.3', '-r,--revision'
 
 // command (and CommandOptions)
 const commandNew1: commander.Command = program.command('action');
-const commandNew2: commander.Command = program.command('action', { isDefault: true, noHelp: true });
+const commandNew2: commander.Command = program.command('action', { isDefault: true, hidden: true, noHelp: true });
 const commandThis1: commander.Command = program.command('exec', 'exec description');
-const commandThis2: commander.Command = program.command('exec', 'exec description', { isDefault: true, noHelp: true, executableFile: 'foo' });
+const commandThis2: commander.Command = program.command('exec', 'exec description', { isDefault: true, hidden: true, noHelp: true, executableFile: 'foo' });
 
 // addCommand
 const addCommandThis: commander.Command = program.addCommand(new commander.Command('abc'));
 
 // arguments
-const argumentsThis: commander.Command = program.arguments('<cmd> [env]')
+const argumentsThis: commander.Command = program.arguments('<cmd> [env]');
 
 // exitOverride
 const exitThis1: commander.Command = program.exitOverride();
-const exitThis2: commander.Command = program.exitOverride((err):never => {
+const exitThis2: commander.Command = program.exitOverride((err): never => {
   return process.exit(err.exitCode);
 });
-const exitThis3: commander.Command = program.exitOverride((err):void => {
+const exitThis3: commander.Command = program.exitOverride((err): void => {
   if (err.code !== 'commander.executeSubCommandAsync') {
     throw err;
   } else {
@@ -63,57 +69,61 @@ const exitThis3: commander.Command = program.exitOverride((err):void => {
 });
 
 // action
-const actionThis1: commander.Command = program.action(() => { });
-const actionThis2: commander.Command = program.action(async () => { });
+const actionThis1: commander.Command = program.action(() => {
+  // do nothing.
+});
+const actionThis2: commander.Command = program.action(async() => {
+  // do nothing.
+});
 
 // option
 const optionThis1: commander.Command = program.option('-a,--alpha');
-const optionThis2: commander.Command = program.option('-p, --peppers', 'Add peppers')
-const optionThis3: commander.Command = program.option('-s, --string [value]', 'default string', 'value')
+const optionThis2: commander.Command = program.option('-p, --peppers', 'Add peppers');
+const optionThis3: commander.Command = program.option('-s, --string [value]', 'default string', 'value');
 const optionThis4: commander.Command = program.option('-b, --boolean', 'default boolean', false);
 
 // example coercion functions from README
 
-function range(val: string) {
+function range(val: string): Number[] {
   return val.split('..').map(Number);
 }
 
-function myParseInt(value: string, dummyPrevious: number) {
+function myParseInt(value: string, dummyPrevious: number): number {
   return parseInt(value);
 }
 
-function increaseVerbosity(dummyValue: string, previous: number) {
+function increaseVerbosity(dummyValue: string, previous: number): number {
   return previous + 1;
 }
 
-function collect(value: string, previous: string[]) {
+function collect(value: string, previous: string[]): string[] {
   return previous.concat([value]);
 }
 
-function commaSeparatedList(value: string, dummyPrevious: string[]) {
+function commaSeparatedList(value: string, dummyPrevious: string[]): string[] {
   return value.split(',');
 }
 
-const optionThis5: commander.Command = program.option('-f, --float <number>', 'float argument', parseFloat)
-const optionThis6: commander.Command = program.option('-f, --float <number>', 'float argument', parseFloat, 3.2)
-const optionThis7: commander.Command = program.option('-i, --integer <number>', 'integer argument', myParseInt)
-const optionThis8: commander.Command = program.option('-i, --integer <number>', 'integer argument', myParseInt, 5)
-const optionThis9: commander.Command = program.option('-v, --verbose', 'verbosity that can be increased', increaseVerbosity, 0)
-const optionThis10: commander.Command = program.option('-c, --collect <value>', 'repeatable value', collect, [])
+const optionThis5: commander.Command = program.option('-f, --float <number>', 'float argument', parseFloat);
+const optionThis6: commander.Command = program.option('-f, --float <number>', 'float argument', parseFloat, 3.2);
+const optionThis7: commander.Command = program.option('-i, --integer <number>', 'integer argument', myParseInt);
+const optionThis8: commander.Command = program.option('-i, --integer <number>', 'integer argument', myParseInt, 5);
+const optionThis9: commander.Command = program.option('-v, --verbose', 'verbosity that can be increased', increaseVerbosity, 0);
+const optionThis10: commander.Command = program.option('-c, --collect <value>', 'repeatable value', collect, []);
 const optionThis11: commander.Command = program.option('-l, --list <items>', 'comma separated list', commaSeparatedList);
 
 // requiredOption, same tests as option
 const requiredOptionThis1: commander.Command = program.requiredOption('-a,--alpha');
-const requiredOptionThis2: commander.Command = program.requiredOption('-p, --peppers', 'Add peppers')
-const requiredOptionThis3: commander.Command = program.requiredOption('-s, --string [value]', 'default string', 'value')
+const requiredOptionThis2: commander.Command = program.requiredOption('-p, --peppers', 'Add peppers');
+const requiredOptionThis3: commander.Command = program.requiredOption('-s, --string [value]', 'default string', 'value');
 const requiredOptionThis4: commander.Command = program.requiredOption('-b, --boolean', 'default boolean', false);
 
-const requiredOptionThis5: commander.Command = program.requiredOption('-f, --float <number>', 'float argument', parseFloat)
-const requiredOptionThis6: commander.Command = program.requiredOption('-f, --float <number>', 'float argument', parseFloat, 3.2)
-const requiredOptionThis7: commander.Command = program.requiredOption('-i, --integer <number>', 'integer argument', myParseInt)
-const requiredOptionThis8: commander.Command = program.requiredOption('-i, --integer <number>', 'integer argument', myParseInt, 5)
-const requiredOptionThis9: commander.Command = program.requiredOption('-v, --verbose', 'verbosity that can be increased', increaseVerbosity, 0)
-const requiredOptionThis10: commander.Command = program.requiredOption('-c, --collect <value>', 'repeatable value', collect, [])
+const requiredOptionThis5: commander.Command = program.requiredOption('-f, --float <number>', 'float argument', parseFloat);
+const requiredOptionThis6: commander.Command = program.requiredOption('-f, --float <number>', 'float argument', parseFloat, 3.2);
+const requiredOptionThis7: commander.Command = program.requiredOption('-i, --integer <number>', 'integer argument', myParseInt);
+const requiredOptionThis8: commander.Command = program.requiredOption('-i, --integer <number>', 'integer argument', myParseInt, 5);
+const requiredOptionThis9: commander.Command = program.requiredOption('-v, --verbose', 'verbosity that can be increased', increaseVerbosity, 0);
+const requiredOptionThis10: commander.Command = program.requiredOption('-c, --collect <value>', 'repeatable value', collect, []);
 const requiredOptionThis11: commander.Command = program.requiredOption('-l, --list <items>', 'comma separated list', commaSeparatedList);
 
 // storeOptionsAsProperties
@@ -133,47 +143,51 @@ const parseThis1: commander.Command = program.parse();
 const parseThis2: commander.Command = program.parse(process.argv);
 const parseThis3: commander.Command = program.parse(['node', 'script.js'], { from: 'node' });
 const parseThis4: commander.Command = program.parse(['node', 'script.js'], { from: 'electron' });
-const parseThis5: commander.Command = program.parse(['--option'], { from: "user" });
+const parseThis5: commander.Command = program.parse(['--option'], { from: 'user' });
 
 // parseAsync, same tests as parse
 const parseAsyncThis1: Promise<commander.Command> = program.parseAsync();
 const parseAsyncThis2: Promise<commander.Command> = program.parseAsync(process.argv);
 const parseAsyncThis3: Promise<commander.Command> = program.parseAsync(['node', 'script.js'], { from: 'node' });
 const parseAsyncThis4: Promise<commander.Command> = program.parseAsync(['node', 'script.js'], { from: 'electron' });
-const parseAsyncThis5: Promise<commander.Command> = program.parseAsync(['--option'], { from: "user" });
+const parseAsyncThis5: Promise<commander.Command> = program.parseAsync(['--option'], { from: 'user' });
 
 // parseOptions (and ParseOptionsResult)
 const { operands, unknown } = program.parseOptions(['node', 'script.js', 'hello']);
 
 // opts
 const opts = program.opts();
 const optsVal1 = opts.foo;
+// eslint-disable-next-line dot-notation
 const opstVale2 = opts['bar'];
 
 // description
-const descriptionThis: commander.Command = program.description("my description");
+const descriptionThis: commander.Command = program.description('my description');
 const descriptionValue: string = program.description();
 
 // alias
-const aliasThis: commander.Command = program.alias("my alias");
+const aliasThis: commander.Command = program.alias('my alias');
 const aliasValue: string = program.alias();
 
+// aliases
+const aliasesThis: commander.Command = program.aliases(['first-alias', 'second-alias']);
+const aliasesValue: string[] = program.aliases();
+
 // usage
-const usageThis: commander.Command = program.usage("my usage");
+const usageThis: commander.Command = program.usage('my usage');
 const usageValue: string = program.usage();
 
 // name
-const nameThis: commander.Command = program.name("my-name");
+const nameThis: commander.Command = program.name('my-name');
 const nameValue: string = program.name();
 
 // outputHelp
 program.outputHelp();
-program.outputHelp((str: string) => { return str });
+program.outputHelp((str: string) => { return str; });
 
 // help
 program.help();
-program.help((str: string) => { return str });
-
+program.help((str: string) => { return str; });
 
 // helpInformation
 const helpInformnationValue: string = program.helpInformation();
@@ -184,18 +198,23 @@ const helpOptionThis2: commander.Command = program.helpOption('-h,--help', 'cust
 const helpOptionThis3: commander.Command = program.helpOption(undefined, 'custom description');
 
 // on
-const onThis: commander.Command = program.on('--help', () => { })
+const onThis: commander.Command = program.on('--help', () => {
+  // do nothing.
+});
 
 // createCommand
 
 const createInstance1: commander.Command = program.createCommand();
 const createInstance2: commander.Command = program.createCommand('name');
 
 class MyCommand extends commander.Command {
-   createCommand(name?: string) {
+  createCommand(name?: string): MyCommand {
     return new MyCommand(name);
   }
-  myFunction() {}
+
+  myFunction(): void {
+    // do nothing.
+  }
 }
 const myProgram = new MyCommand();
 myProgram.myFunction();

diff --git a/typings/index.d.ts b/typings/index.d.ts
@@ -9,7 +9,7 @@ declare namespace commander {
     message: string;
     nestedError?: string;
   }
-  type CommanderErrorConstructor = { new (exitCode: number, code: string, message: string): CommanderError };
+  type CommanderErrorConstructor = new (exitCode: number, code: string, message: string) => CommanderError;
 
   interface Option {
     flags: string;
@@ -21,7 +21,7 @@ declare namespace commander {
     long: string;
     description: string;
   }
-  type OptionConstructor = { new (flags: string, description?: string): Option };
+  type OptionConstructor = new (flags: string, description?: string) => Option;
 
   interface ParseOptions {
     from: 'node' | 'electron' | 'user';
@@ -35,21 +35,21 @@ declare namespace commander {
     commands: Command[];
 
     /**
-     * Set the program version to `str`. 
+     * Set the program version to `str`.
      *
      * This method auto-registers the "-V, --version" flag
      * which will print the version number when passed.
-     * 
+     *
      * You can optionally supply the  flags and description to override the defaults.
      */
     version(str: string, flags?: string, description?: string): this;
 
     /**
      * Define a command, implemented using an action handler.
-     * 
+     *
      * @remarks
      * The command description is supplied using `.description`, not as a parameter to `.command`.
-     * 
+     *
      * @example
      * ```ts
      *  program
@@ -59,31 +59,31 @@ declare namespace commander {
      *      console.log('clone command called');
      *    });
      * ```
-     * 
+     *
      * @param nameAndArgs - command name and arguments, args are  `<required>` or `[optional]` and last may also be `variadic...`
      * @param opts - configuration options
      * @returns new command
      */
     command(nameAndArgs: string, opts?: CommandOptions): ReturnType<this['createCommand']>;
     /**
      * Define a command, implemented in a separate executable file.
-     * 
+     *
      * @remarks
      * The command description is supplied as the second parameter to `.command`.
-     * 
+     *
      * @example
      * ```ts
      *  program
      *    .command('start <service>', 'start named service')
      *    .command('stop [service]', 'stop named serice, or all if no name supplied');
      * ```
-     * 
+     *
      * @param nameAndArgs - command name and arguments, args are  `<required>` or `[optional]` and last may also be `variadic...`
      * @param description - description of executable command
      * @param opts - configuration options
-     * @returns top level command for chaining more command definitions
+     * @returns `this` command for chaining
      */
-    command(nameAndArgs: string, description: string, opts?: commander.CommandOptions): this;
+    command(nameAndArgs: string, description: string, opts?: commander.ExecutableCommandOptions): this;
 
     /**
      * Factory routine to create a new unattached command.
@@ -92,20 +92,20 @@ declare namespace commander {
      * create the command. You can override createCommand to customise subcommands.
      */
     createCommand(name?: string): Command;
-    
+
     /**
      * Add a prepared subcommand.
-     * 
+     *
      * See .command() for creating an attached subcommand which inherits settings from its parent.
-     * 
-     * @returns parent command for chaining
+     *
+     * @returns `this` command for chaining
      */
-    addCommand(cmd: Command): this;
+    addCommand(cmd: Command, opts?: CommandOptions): this;
 
     /**
-     * Define argument syntax for the top-level command.
+     * Define argument syntax for command.
      *
-     * @returns Command for chaining
+     * @returns `this` command for chaining
      */
     arguments(desc: string): this;
 
@@ -125,7 +125,7 @@ declare namespace commander {
      *           // output help here
      *        });
      *
-     * @returns Command for chaining
+     * @returns `this` command for chaining
      */
     action(fn: (...args: any[]) => void | Promise<void>): this;
 
@@ -169,7 +169,7 @@ declare namespace commander {
      *     // optional argument
      *     program.option('-c, --cheese [type]', 'add cheese [marble]');
      *
-     * @returns Command for chaining
+     * @returns `this` command for chaining
      */
     option(flags: string, description?: string, defaultValue?: string | boolean): this;
     option(flags: string, description: string, regexp: RegExp, defaultValue?: string | boolean): this;
@@ -185,34 +185,33 @@ declare namespace commander {
     requiredOption(flags: string, description: string, regexp: RegExp, defaultValue?: string | boolean): this;
     requiredOption<T>(flags: string, description: string, fn: (value: string, previous: T) => T, defaultValue?: T): this;
 
-
     /**
      * Whether to store option values as properties on command object,
      * or store separately (specify false). In both cases the option values can be accessed using .opts().
      *
-     * @return Command for chaining
+     * @returns `this` command for chaining
      */
     storeOptionsAsProperties(value?: boolean): this;
 
     /**
      * Whether to pass command to action handler,
      * or just the options (specify false).
-     * 
-     * @return Command for chaining
+     *
+     * @returns `this` command for chaining
      */
     passCommandToAction(value?: boolean): this;
 
     /**
      * Allow unknown options on the command line.
      *
      * @param [arg] if `true` or omitted, no error will be thrown for unknown options.
-     * @returns Command for chaining
+     * @returns `this` command for chaining
      */
     allowUnknownOption(arg?: boolean): this;
 
     /**
      * Parse `argv`, setting options and invoking commands when defined.
-     * 
+     *
      * The default expectation is that the arguments are from node and have the application as argv[0]
      * and the script being run in argv[1], with user parameters after that.
      *
@@ -221,16 +220,16 @@ declare namespace commander {
      *      program.parse(process.argv);
      *      program.parse(); // implicitly use process.argv and auto-detect node vs electron conventions
      *      program.parse(my-args, { from: 'user' }); // just user supplied arguments, nothing special about argv[0]
-     * 
-     * @returns Command for chaining
+     *
+     * @returns `this` command for chaining
      */
     parse(argv?: string[], options?: ParseOptions): this;
 
     /**
      * Parse `argv`, setting options and invoking commands when defined.
-     * 
+     *
      * Use parseAsync instead of parse if any of your action handlers are async. Returns a Promise.
-     * 
+     *
      * The default expectation is that the arguments are from node and have the application as argv[0]
      * and the script being run in argv[1], with user parameters after that.
      *
@@ -264,8 +263,8 @@ declare namespace commander {
 
     /**
      * Set the description.
-     * 
-     * @returns Command for chaining
+     *
+     * @returns `this` command for chaining
      */
     description(str: string, argsDescription?: {[argName: string]: string}): this;
     /**
@@ -275,19 +274,34 @@ declare namespace commander {
 
     /**
      * Set an alias for the command.
-     * 
-     * @returns Command for chaining
+     *
+     * You may call more than once to add multiple aliases. Only the first alias is shown in the auto-generated help.
+     *
+     * @returns `this` command for chaining
      */
     alias(alias: string): this;
     /**
      * Get alias for the command.
      */
     alias(): string;
 
+    /**
+     * Set aliases for the command.
+     *
+     * Only the first alias is shown in the auto-generated help.
+     *
+     * @returns `this` command for chaining
+     */
+    aliases(aliases: string[]): this;
+    /**
+     * Get aliases for the command.
+     */
+    aliases(): string[];
+
     /**
      * Set the command usage.
-     * 
-     * @returns Command for chaining
+     *
+     * @returns `this` command for chaining
      */
     usage(str: string): this;
     /**
@@ -297,8 +311,8 @@ declare namespace commander {
 
     /**
      * Set the name of the command.
-     * 
-     * @returns Command for chaining
+     *
+     * @returns `this` command for chaining
      */
     name(str: string): this;
     /**
@@ -318,21 +332,21 @@ declare namespace commander {
      * Return command help documentation.
      */
     helpInformation(): string;
-    
+
     /**
      * You can pass in flags and a description to override the help
      * flags and help description for your command.
      */
     helpOption(flags?: string, description?: string): this;
 
-    /** 
+    /**
      * Output help information and exit.
      */
     help(cb?: (str: string) => string): never;
 
     /**
      * Add a listener (callback) for when events occur. (Implemented using EventEmitter.)
-     * 
+     *
      * @example
      *     program
      *       .on('--help', () -> {
@@ -341,28 +355,32 @@ declare namespace commander {
      */
     on(event: string | symbol, listener: (...args: any[]) => void): this;
   }
-  type CommandConstructor = { new (name?: string): Command };
-
+  type CommandConstructor = new (name?: string) => Command;
 
-    interface CommandOptions {
-        noHelp?: boolean;
-        isDefault?: boolean;
-        executableFile?: string;
-    }
+  interface CommandOptions {
+    noHelp?: boolean; // old name for hidden
+    hidden?: boolean;
+    isDefault?: boolean;
+  }
+  interface ExecutableCommandOptions extends CommandOptions {
+    executableFile?: string;
+  }
 
-    interface ParseOptionsResult {
-        operands: string[];
-        unknown: string[];
-    }
+  interface ParseOptionsResult {
+    operands: string[];
+    unknown: string[];
+  }
 
-    interface CommanderStatic extends Command {
-        program: Command;
-        Command: CommandConstructor;
-        Option: OptionConstructor;
-        CommanderError:CommanderErrorConstructor;
-      }
+  interface CommanderStatic extends Command {
+    program: Command;
+    Command: CommandConstructor;
+    Option: OptionConstructor;
+    CommanderError: CommanderErrorConstructor;
+  }
 
 }
 
+// Declaring namespace AND global
+// eslint-disable-next-line no-redeclare
 declare const commander: commander.CommanderStatic;
 export = commander;