Add optional summary for short form of subcommand description.

Readme.md

@@ -35,6 +35,7 @@ Read this in other languages: English | [简体中文](./Readme_zh-CN.md)
     - [Display help from code](#display-help-from-code)
     - [.name](#name)
     - [.usage](#usage)
+    - [.description and .summary](#description-and-summary)
     - [.helpOption(flags, description)](#helpoptionflags-description)
     - [.addHelpCommand()](#addhelpcommand)
     - [More configuration](#more-configuration-2)
@@ -814,10 +815,11 @@ error: unknown option '--unknown'
 (add --help for additional information)
 ```
 
-You can also show suggestions after an error for an unknown command or option.
+The default behaviour is to suggest correct spelling after an error for an unknown command or option. You
+can disable this.
 
 ```js
-program.showSuggestionAfterError();
+program.showSuggestionAfterError(false);
 ```
 
 ```console
@@ -866,6 +868,20 @@ The help will start with:
 Usage: my-command [global options] command
 ```
 
+### .description and .summary
+
+The description appears in the help for the command. You can optionally supply a shorter
+summary to use when listed as a subcommand of the program.
+
+```js
+program
+  .command("duplicate")
+  .summary("make a copy")
+  .description(`Make a copy of the current project.
+This may require additional disk space.
+  `);
+```
+
 ### .helpOption(flags, description)
 
 By default every command has a help option. You may change the default help flags and description. Pass false to disable the built-in help option.

lib/command.js

@@ -48,6 +48,7 @@ class Command extends EventEmitter {
     this._aliases = [];
     this._combineFlagAndOptionalValue = true;
     this._description = '';
+    this._summary = '';
     this._argsDescription = undefined; // legacy
     this._enablePositionalOptions = false;
     this._passThroughOptions = false;
@@ -1767,7 +1768,7 @@ Expecting one of '${allowedValues.join("', '")}'`);
   }
 
   /**
-   * Set the description to `str`.
+   * Set the description.
    *
    * @param {string} [str]
    * @param {Object} [argsDescription]
@@ -1782,6 +1783,18 @@ Expecting one of '${allowedValues.join("', '")}'`);
     return this;
   }
 
+  /**
+   * Set the summary. Used when listed as subcommand of parent.
+   *
+   * @param {string} [str]
+   * @return {string|Command}
+   */
+  summary(str) {
+    if (str === undefined) return this._summary;
+    this._summary = str;
+    return this;
+  }
+
   /**
    * Set an alias for the command.
    *

lib/help.js

@@ -215,15 +215,16 @@ class Help {
   }
 
   /**
-   * Get the command description to show in the list of subcommands.
+   * Get the subcommand summary to show in the list of subcommands.
+   * (Fallback to description for backwards compatiblity.)
    *
    * @param {Command} cmd
    * @returns {string}
    */
 
   subcommandDescription(cmd) {
     // @ts-ignore: overloaded return type
-    return cmd.description();
+    return cmd.summary() || cmd.description();
   }
 
   /**

tests/command.summary.test.js

@@ -0,0 +1,8 @@
+const commander = require('../');
+
+test('when set summary then get summary', () => {
+  const program = new commander.Command();
+  const summary = 'abcdef';
+  program.summary(summary);
+  expect(program.summary()).toMatch(summary);
+});

tests/help.subcommandDescription.test.js

@@ -0,0 +1,37 @@
+const commander = require('../');
+
+// These are tests of the Help class, not of the Command help.
+// There is some overlap with the higher level Command tests (which predate Help).
+
+describe('subcommandDescription', () => {
+  test('when program has no summary or description then empty string', () => {
+    const program = new commander.Command();
+    const helper = new commander.Help();
+    expect(helper.subcommandDescription(program)).toEqual('');
+  });
+
+  test('when program has summary then return summary', () => {
+    const summary = 'summary';
+    const program = new commander.Command();
+    program.summary(summary);
+    const helper = new commander.Help();
+    expect(helper.subcommandDescription(program)).toEqual(summary);
+  });
+
+  test('when program has description then return description', () => {
+    const description = 'description';
+    const program = new commander.Command();
+    program.description(description);
+    const helper = new commander.Help();
+    expect(helper.subcommandDescription(program)).toEqual(description);
+  });
+
+  test('when program has summary and description then return summary', () => {
+    const summary = 'summary';
+    const program = new commander.Command();
+    program.summary(summary);
+    program.description('description');
+    const helper = new commander.Help();
+    expect(helper.subcommandDescription(program)).toEqual(summary);
+  });
+});

typings/index.d.ts

@@ -202,7 +202,7 @@ export class Help {
 
   /** Get the command term to show in the list of subcommands. */
   subcommandTerm(cmd: Command): string;
-  /** Get the command description to show in the list of subcommands. */
+  /** Get the command summary to show in the list of subcommands. */
   subcommandDescription(cmd: Command): string;
   /** Get the option term to show in the list of options. */
   optionTerm(option: Option): string;
@@ -718,6 +718,18 @@ export class Command {
    */
   description(): string;
 
+  /**
+   * Set the summary. Used when listed as subcommand of parent.
+   *
+   * @returns `this` command for chaining
+   */
+
+  summary(str: string): this;
+  /**
+   * Get the summary.
+   */
+  summary(): string;
+
   /**
    * Set an alias for the command.
    *

typings/index.test-d.ts

@@ -239,6 +239,10 @@ expectType<commander.Command>(program.description('my description'));
 expectType<string>(program.description());
 expectType<commander.Command>(program.description('my description of command with arg foo', { foo: 'foo description' })); // deprecated
 
+// summary
+expectType<commander.Command>(program.summary('my summary'));
+expectType<string>(program.summary());
+
 // alias
 expectType<commander.Command>(program.alias('my alias'));
 expectType<string>(program.alias());