Add save/restore state to allow multiple calls to parse

Readme.md

@@ -959,8 +959,6 @@ program.parse(['--port', '80'], { from: 'user' }); // just user supplied argumen
 
 Use parseAsync instead of parse if any of your action handlers are async.
 
-If you want to parse multiple times, create a new program each time. Calling parse does not clear out any previous state.
-
 ### Parsing Configuration
 
 If the default parsing does not suit your needs, there are some behaviours to support other usage patterns.

lib/command.js

@@ -55,6 +55,7 @@ class Command extends EventEmitter {
     /** @type {(boolean | string)} */
     this._showHelpAfterError = false;
     this._showSuggestionAfterError = true;
+    this._savedState = null; // used in save/restoreStateBeforeParse
 
     // see configureOutput() for docs
     this._outputConfiguration = {
@@ -1069,6 +1070,7 @@ Expecting one of '${allowedValues.join("', '")}'`);
    */
 
   parse(argv, parseOptions) {
+    this._prepareForParse();
     const userArgs = this._prepareUserArgs(argv, parseOptions);
     this._parseCommand([], userArgs);
 
@@ -1097,12 +1099,62 @@ Expecting one of '${allowedValues.join("', '")}'`);
    */
 
   async parseAsync(argv, parseOptions) {
+    this._prepareForParse();
     const userArgs = this._prepareUserArgs(argv, parseOptions);
     await this._parseCommand([], userArgs);
 
     return this;
   }
 
+  _prepareForParse() {
+    if (this._savedState === null) {
+      this.saveStateBeforeParse();
+    } else {
+      this.restoreStateBeforeParse();
+    }
+  }
+
+  /**
+   * Called the first time parse is called to save state and allow a restore before subsequent calls to parse.
+   * Not usually called directly, but available for subclasses to save their custom state.
+   *
+   * This is called in a lazy way. Only commands used in parsing chain will have state saved.
+   */
+  saveStateBeforeParse() {
+    this._savedState = {
+      // name is stable if supplied by author, but may be unspecified for root command and deduced during parsing
+      _name: this._name,
+      // option values before parse have default values (including false for negated options)
+      // shallow clones
+      _optionValues: { ...this._optionValues },
+      _optionValueSources: { ...this._optionValueSources },
+    };
+  }
+
+  /**
+   * Restore state before parse for calls after the first.
+   * Not usually called directly, but available for subclasses to save their custom state.
+   *
+   * This is called in a lazy way. Only commands used in parsing chain will have state restored.
+   */
+  restoreStateBeforeParse() {
+    if (this._storeOptionsAsProperties)
+      throw new Error(`Can not call parse again when storeOptionsAsProperties is true.
+- either make a new Command for each call to parse, or stop storing options as properties`);
+
+    // clear state from _prepareUserArgs
+    this._name = this._savedState._name;
+    this._scriptPath = null;
+    this.rawArgs = [];
+    // clear state from setOptionValueWithSource
+    this._optionValues = { ...this._savedState._optionValues };
+    this._optionValueSources = { ...this._savedState._optionValueSources };
+    // clear state from _parseCommand
+    this.args = [];
+    // clear state from _processArguments
+    this.processedArgs = [];
+  }
+
   /**
    * Throw if expected executable is missing. Add lots of help for author.
    *
@@ -1283,6 +1335,7 @@ Expecting one of '${allowedValues.join("', '")}'`);
     const subCommand = this._findCommand(commandName);
     if (!subCommand) this.help({ error: true });
 
+    subCommand._prepareForParse();
     let promiseChain;
     promiseChain = this._chainOrCallSubCommandHook(
       promiseChain,
@@ -1660,6 +1713,8 @@ Expecting one of '${allowedValues.join("', '")}'`);
    * Parse options from `argv` removing known options,
    * and return argv split into operands and unknown arguments.
    *
+   * Side effects: modifies command by storing options. Does not reset state if called again.
+   *
    * Examples:
    *
    *     argv => operands, unknown

tests/command.parse.test.js

@@ -199,3 +199,221 @@ describe('parseAsync parameter is treated as readonly, per TypeScript declaratio
     expect(program.rawArgs).toEqual(oldRawArgs);
   });
 });
+
+describe('.parse() called multiple times', () => {
+  test('when use boolean options then option values reset', () => {
+    const program = new commander.Command().option('--black').option('--white');
+
+    program.parse(['--black'], { from: 'user' });
+    expect(program.opts()).toEqual({ black: true });
+
+    program.parse(['--white'], { from: 'user' });
+    expect(program.opts()).toEqual({ white: true });
+  });
+
+  test('when use options with option-argument then option values and sources reset', () => {
+    const program = new commander.Command()
+      .option('-f, --foo <value>')
+      .option('-b, --bar <value>');
+
+    program.parse(['--foo', 'FOO'], { from: 'user' });
+    expect(program.opts()).toEqual({ foo: 'FOO' });
+    expect(program.getOptionValueSource('foo')).toEqual('cli');
+    expect(program.getOptionValueSource('bar')).toBeUndefined();
+
+    program.parse(['--bar', 'BAR'], { from: 'user' });
+    expect(program.opts()).toEqual({ bar: 'BAR' });
+    expect(program.getOptionValueSource('foo')).toBeUndefined();
+    expect(program.getOptionValueSource('bar')).toEqual('cli');
+  });
+
+  test('when use options with option-argument and default then option values and sources reset', () => {
+    const program = new commander.Command()
+      .option('-f, --foo <value>', 'description', 'default-FOO')
+      .option('-b, --bar <value>', 'description', 'default-BAR');
+
+    program.parse(['--foo', 'FOO'], { from: 'user' });
+    expect(program.opts()).toEqual({ foo: 'FOO', bar: 'default-BAR' });
+    expect(program.getOptionValueSource('foo')).toEqual('cli');
+    expect(program.getOptionValueSource('bar')).toEqual('default');
+
+    program.parse(['--bar', 'BAR'], { from: 'user' });
+    expect(program.opts()).toEqual({ foo: 'default-FOO', bar: 'BAR' });
+    expect(program.getOptionValueSource('foo')).toEqual('default');
+    expect(program.getOptionValueSource('bar')).toEqual('cli');
+  });
+
+  test('when use negated options then option values reset', () => {
+    const program = new commander.Command()
+      .option('--no-foo')
+      .option('--no-bar');
+
+    program.parse(['--no-foo'], { from: 'user' });
+    expect(program.opts()).toEqual({ foo: false, bar: true });
+
+    program.parse(['--no-bar'], { from: 'user' });
+    expect(program.opts()).toEqual({ foo: true, bar: false });
+  });
+
+  test('when use variadic option then option values reset', () => {
+    const program = new commander.Command().option('--var <items...>');
+
+    program.parse(['--var', 'a', 'b'], { from: 'user' });
+    expect(program.opts()).toEqual({ var: ['a', 'b'] });
+
+    program.parse(['--var', 'c'], { from: 'user' });
+    expect(program.opts()).toEqual({ var: ['c'] });
+  });
+
+  test('when use collect example then option value resets', () => {
+    function collect(value, previous) {
+      return previous.concat([value]);
+    }
+    const program = new commander.Command();
+    program.option('-c, --collect <value>', 'repeatable value', collect, []);
+
+    program.parse(['-c', 'a', '-c', 'b'], { from: 'user' });
+    expect(program.opts()).toEqual({ collect: ['a', 'b'] });
+
+    program.parse(['-c', 'c'], { from: 'user' });
+    expect(program.opts()).toEqual({ collect: ['c'] });
+  });
+
+  test('when use increaseVerbosity example then option value resets', () => {
+    function increaseVerbosity(dummyValue, previous) {
+      return previous + 1;
+    }
+    const program = new commander.Command();
+    program.option(
+      '-v, --verbose',
+      'verbosity that can be increased',
+      increaseVerbosity,
+      0,
+    );
+
+    program.parse(['-vvv'], { from: 'user' });
+    expect(program.opts()).toEqual({ verbose: 3 });
+    program.parse(['-vv'], { from: 'user' });
+
+    expect(program.opts()).toEqual({ verbose: 2 });
+    program.parse([], { from: 'user' });
+    expect(program.opts()).toEqual({ verbose: 0 });
+  });
+
+  test('when use parse and parseAsync then option values reset', async () => {
+    const program = new commander.Command().option('--black').option('--white');
+
+    program.parse(['--black'], { from: 'user' });
+    expect(program.opts()).toEqual({ black: true });
+    await program.parseAsync(['--white'], { from: 'user' });
+    expect(program.opts()).toEqual({ white: true });
+  });
+
+  test('when call subcommand then option values reset (program and subcommand)', () => {
+    const program = new commander.Command().option('--black').option('--white');
+    const subcommand = program.command('sub').option('--red').option('--green');
+
+    program.parse(['--black', 'sub', '--red'], { from: 'user' });
+    expect(subcommand.optsWithGlobals()).toEqual({ black: true, red: true });
+
+    program.parse(['--white', 'sub', '--green'], { from: 'user' });
+    expect(subcommand.optsWithGlobals()).toEqual({ white: true, green: true });
+  });
+
+  test('when call different subcommand then no reset because lazy', () => {
+    // This is not a required behaviour, but is the intended behaviour.
+    const program = new commander.Command();
+    const sub1 = program.command('sub1').option('--red');
+    const sub2 = program.command('sub2').option('--green');
+
+    program.parse(['sub1', '--red'], { from: 'user' });
+    expect(sub1.opts()).toEqual({ red: true });
+    expect(sub2.opts()).toEqual({});
+
+    program.parse(['sub2', '--green'], { from: 'user' });
+    expect(sub1.opts()).toEqual({ red: true });
+    expect(sub2.opts()).toEqual({ green: true });
+  });
+
+  test('when parse with different implied program name then name changes', () => {
+    const program = new commander.Command();
+
+    program.parse(['node', 'script1.js']);
+    expect(program.name()).toEqual('script1');
+
+    program.parse(['electron', 'script2.js']);
+    expect(program.name()).toEqual('script2');
+  });
+
+  test('when parse with different arguments then args change', () => {
+    // weak test, would work without store/reset!
+    const program = new commander.Command()
+      .argument('<first>')
+      .argument('[second]');
+
+    program.parse(['one', 'two'], { from: 'user' });
+    expect(program.args).toEqual(['one', 'two']);
+
+    program.parse(['alpha'], { from: 'user' });
+    expect(program.args).toEqual(['alpha']);
+  });
+
+  test('when parse with different arguments then rawArgs change', () => {
+    // weak test, would work without store/reset!
+    const program = new commander.Command()
+      .argument('<first>')
+      .option('--white')
+      .option('--black');
+
+    program.parse(['--white', 'one'], { from: 'user' });
+    expect(program.rawArgs).toEqual(['--white', 'one']);
+
+    program.parse(['--black', 'two'], { from: 'user' });
+    expect(program.rawArgs).toEqual(['--black', 'two']);
+  });
+
+  test('when parse with different arguments then processedArgs change', () => {
+    // weak test, would work without store/reset!
+    const program = new commander.Command().argument(
+      '<first>',
+      'first arg',
+      parseFloat,
+    );
+
+    program.parse([123], { from: 'user' });
+    expect(program.processedArgs).toEqual([123]);
+
+    program.parse([456], { from: 'user' });
+    expect(program.processedArgs).toEqual([456]);
+  });
+
+  test('when parse subcommand then reset state before preSubcommand hook called', () => {
+    let hookCalled = false;
+    const program = new commander.Command().hook(
+      'preSubcommand',
+      (thisCommand, subcommand) => {
+        hookCalled = true;
+        expect(subcommand.opts()).toEqual({});
+      },
+    );
+    const subcommand = program.command('sub').option('--red').option('--green');
+
+    hookCalled = false;
+    program.parse(['sub', '--red'], { from: 'user' });
+    expect(hookCalled).toBe(true);
+    expect(subcommand.opts()).toEqual({ red: true });
+
+    hookCalled = false;
+    program.parse(['sub', '--green'], { from: 'user' });
+    expect(hookCalled).toBe(true);
+    expect(subcommand.opts()).toEqual({ green: true });
+  });
+
+  test('when using storeOptionsAsProperties then throw on second parse', () => {
+    const program = new commander.Command().storeOptionsAsProperties();
+    program.parse();
+    expect(() => {
+      program.parse();
+    }).toThrow();
+  });
+});

typings/index.d.ts

@@ -821,10 +821,28 @@ export class Command {
     parseOptions?: ParseOptions,
   ): Promise<this>;
 
+  /**
+   * Called the first time parse is called to save state and allow a restore before subsequent calls to parse.
+   * Not usually called directly, but available for subclasses to save their custom state.
+   *
+   * This is called in a lazy way. Only commands used in parsing chain will have state saved.
+   */
+  saveStateBeforeParse(): void;
+
+  /**
+   * Restore state before parse for calls after the first.
+   * Not usually called directly, but available for subclasses to save their custom state.
+   *
+   * This is called in a lazy way. Only commands used in parsing chain will have state restored.
+   */
+  restoreStateBeforeParse(): void;
+
   /**
    * Parse options from `argv` removing known options,
    * and return argv split into operands and unknown arguments.
    *
+   * Side effects: modifies command by storing options. Does not reset state if called again.
+   *
    *     argv => operands, unknown
    *     --known kkk op => [op], []
    *     op --known kkk => [op], []

typings/index.test-d.ts

@@ -370,6 +370,10 @@ expectType<{ operands: string[]; unknown: string[] }>(
   program.parseOptions(['node', 'script.js', 'hello']),
 );
 
+// save/restore state
+expectType<void>(program.saveStateBeforeParse());
+expectType<void>(program.restoreStateBeforeParse());
+
 // opts
 const opts = program.opts();
 expectType<commander.OptionValues>(opts);