Add .allowExcessArguments() and error message

index.js

@@ -535,6 +535,7 @@ class Command extends EventEmitter {
     this.options = [];
     this.parent = null;
     this._allowUnknownOption = false;
+    this._allowExcessArguments = true;
     this._args = [];
     this.rawArgs = null;
     this._scriptPath = null;
@@ -1170,6 +1171,17 @@ Read more on https://git.io/JJc0W`);
     return this;
   };
 
+  /**
+   * Allow excess arguments on the command line.
+   *
+   * @param {Boolean} [allowExcess] - if `true` or omitted, no error will be thrown
+   * for excess arguments.
+   */
+  allowExcessArguments(allowExcess) {
+    this._allowExcessArguments = (allowExcess === undefined) || !!allowExcess;
+    return 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().
@@ -1492,14 +1504,19 @@ Read more on https://git.io/JJc0W`);
 
       const commandEvent = `command:${this.name()}`;
       if (this._actionHandler) {
+        // Check expected arguments and collect variadic together.
         const args = this.args.slice();
         this._args.forEach((arg, i) => {
           if (arg.required && args[i] == null) {
             this.missingArgument(arg.name);
           } else if (arg.variadic) {
             args[i] = args.splice(i);
+            args.length = Math.min(i + 1, args.length);
           }
         });
+        if (args.length > this._args.length) {
+          this._excessArguments(args);
+        }
 
         this._actionHandler(args);
         if (this.parent) this.parent.emit(commandEvent, operands, unknown); // legacy
@@ -1753,6 +1770,23 @@ Read more on https://git.io/JJc0W`);
     this._displayError(1, 'commander.unknownOption', message);
   };
 
+  /**
+   * Excess arguments, more than expected.
+   *
+   * @param {string[]} receivedArgs
+   * @api private
+   */
+
+  _excessArguments(receivedArgs) {
+    if (this._allowExcessArguments) return;
+
+    const expected = this._args.length;
+    const s = (expected === 1) ? '' : 's';
+    const forSubcommand = this.parent ? ` for '${this.name()}'` : '';
+    const message = `error: too many arguments${forSubcommand}. Expected ${expected} argument${s} but got ${receivedArgs.length}.`;
+    this._displayError(1, 'commander.excessArguments', message);
+  };
+
   /**
    * Unknown command.
    *

tests/command.allowExcessArguments.test.js

@@ -0,0 +1,145 @@
+const commander = require('../');
+
+// Not testing output, just testing whether an error is detected.
+
+describe('allowUnknownOption', () => {
+  // Optional. Use internal knowledge to suppress output to keep test output clean.
+  let writeErrorSpy;
+
+  beforeAll(() => {
+    writeErrorSpy = jest.spyOn(process.stderr, 'write').mockImplementation(() => { });
+  });
+
+  afterEach(() => {
+    writeErrorSpy.mockClear();
+  });
+
+  afterAll(() => {
+    writeErrorSpy.mockRestore();
+  });
+
+  test('when specify excess program argument then ignored by default', () => {
+    const program = new commander.Command();
+    program
+      .exitOverride()
+      .action(() => {});
+
+    expect(() => {
+      program.parse(['excess'], { from: 'user' });
+    }).not.toThrow();
+  });
+
+  test('when specify excess program argument and allowExcessArguments(false) then error', () => {
+    const program = new commander.Command();
+    program
+      .exitOverride()
+      .allowExcessArguments(false)
+      .action(() => {});
+
+    expect(() => {
+      program.parse(['excess'], { from: 'user' });
+    }).toThrow();
+  });
+
+  test('when specify excess program argument and allowExcessArguments() then no error', () => {
+    const program = new commander.Command();
+    program
+      .exitOverride()
+      .allowExcessArguments()
+      .action(() => {});
+
+    expect(() => {
+      program.parse(['excess'], { from: 'user' });
+    }).not.toThrow();
+  });
+
+  test('when specify excess program argument and allowExcessArguments(true) then no error', () => {
+    const program = new commander.Command();
+    program
+      .exitOverride()
+      .allowExcessArguments(true)
+      .action(() => {});
+
+    expect(() => {
+      program.parse(['excess'], { from: 'user' });
+    }).not.toThrow();
+  });
+
+  test('when specify excess command argument then no error (by default)', () => {
+    const program = new commander.Command();
+    program
+      .exitOverride()
+      .command('sub')
+      .action(() => { });
+
+    expect(() => {
+      program.parse(['sub', 'excess'], { from: 'user' });
+    }).not.toThrow();
+  });
+
+  test('when specify excess command argument and allowExcessArguments(false) then error', () => {
+    const program = new commander.Command();
+    program
+      .exitOverride()
+      .command('sub')
+      .allowUnknownOption()
+      .allowExcessArguments(false)
+      .action(() => { });
+
+    expect(() => {
+      program.parse(['sub', 'excess'], { from: 'user' });
+    }).toThrow();
+  });
+
+  test('when specify expected arg and allowExcessArguments(false) then no error', () => {
+    const program = new commander.Command();
+    program
+      .arguments('<file>')
+      .exitOverride()
+      .allowExcessArguments(false)
+      .action(() => {});
+
+    expect(() => {
+      program.parse(['file'], { from: 'user' });
+    }).not.toThrow();
+  });
+
+  test('when specify excess after <arg> and allowExcessArguments(false) then error', () => {
+    const program = new commander.Command();
+    program
+      .arguments('<file>')
+      .exitOverride()
+      .allowExcessArguments(false)
+      .action(() => {});
+
+    expect(() => {
+      program.parse(['file', 'excess'], { from: 'user' });
+    }).toThrow();
+  });
+
+  test('when specify excess after [arg] and allowExcessArguments(false) then error', () => {
+    const program = new commander.Command();
+    program
+      .arguments('[file]')
+      .exitOverride()
+      .allowExcessArguments(false)
+      .action(() => {});
+
+    expect(() => {
+      program.parse(['file', 'excess'], { from: 'user' });
+    }).toThrow();
+  });
+
+  test('when specify args for [args...] and allowExcessArguments(false) then no error', () => {
+    const program = new commander.Command();
+    program
+      .arguments('[files...]')
+      .exitOverride()
+      .allowExcessArguments(false)
+      .action(() => {});
+
+    expect(() => {
+      program.parse(['file1', 'file2', 'file3'], { from: 'user' });
+    }).not.toThrow();
+  });
+});

tests/command.chain.test.js

@@ -70,6 +70,12 @@ describe('Command methods that should return this for chaining', () => {
     expect(result).toBe(program);
   });
 
+  test('when call .allowExcessArguments() then returns this', () => {
+    const program = new Command();
+    const result = program.allowExcessArguments();
+    expect(result).toBe(program);
+  });
+
   test('when call .storeOptionsAsProperties() then returns this', () => {
     const program = new Command();
     const result = program.storeOptionsAsProperties();

tests/command.exitOverride.test.js

@@ -120,6 +120,43 @@ describe('.exitOverride and error details', () => {
     expectCommanderError(caughtErr, 1, 'commander.missingArgument', "error: missing required argument 'arg-name'");
   });
 
+  test('when specify excess argument then throw CommanderError', () => {
+    const program = new commander.Command();
+    program
+      .exitOverride()
+      .allowExcessArguments(false)
+      .action(() => { });
+
+    let caughtErr;
+    try {
+      program.parse(['node', 'test', 'excess']);
+    } catch (err) {
+      caughtErr = err;
+    }
+
+    expect(stderrSpy).toHaveBeenCalled();
+    expectCommanderError(caughtErr, 1, 'commander.excessArguments', 'error: too many arguments. Expected 0 arguments but got 1.');
+  });
+
+  test('when specify command with excess argument then throw CommanderError', () => {
+    const program = new commander.Command();
+    program
+      .exitOverride()
+      .command('speak')
+      .allowExcessArguments(false)
+      .action(() => { });
+
+    let caughtErr;
+    try {
+      program.parse(['node', 'test', 'speak', 'excess']);
+    } catch (err) {
+      caughtErr = err;
+    }
+
+    expect(stderrSpy).toHaveBeenCalled();
+    expectCommanderError(caughtErr, 1, 'commander.excessArguments', "error: too many arguments for 'speak'. Expected 0 arguments but got 1.");
+  });
+
   test('when specify --help then throw CommanderError', () => {
     const writeSpy = jest.spyOn(process.stdout, 'write').mockImplementation(() => { });
     const program = new commander.Command();

typings/commander-tests.ts

@@ -159,6 +159,10 @@ const combineFlagAndOptionalValueThis2: commander.Command = program.combineFlagA
 const allowUnknownOptionThis1: commander.Command = program.allowUnknownOption();
 const allowUnknownOptionThis2: commander.Command = program.allowUnknownOption(false);
 
+// allowExcessArguments
+const allowExcessArgumentsThis1: commander.Command = program.allowExcessArguments();
+const allowExcessArgumentsThis2: commander.Command = program.allowExcessArguments(false);
+
 // parse
 const parseThis1: commander.Command = program.parse();
 const parseThis2: commander.Command = program.parse(process.argv);

typings/index.d.ts

@@ -403,6 +403,13 @@ declare namespace commander {
      */
     allowUnknownOption(allowUnknown?: boolean): this;
 
+    /**
+     * Allow excess arguments on the command line.
+     *
+     * @returns `this` command for chaining
+     */
+    allowExcessArguments(allowExcess?: boolean): this;
+
     /**
      * Parse `argv`, setting options and invoking commands when defined.
      *