Rework default program name, and searching for subcommands (#1571)

* Simplify how default program name found. Just use args.

* Rework search for executable files

* Adjust error messaging, still WIP

* Add executableDir and use searching for subcommands

* Wording improvements

* Add TypeScript for nameFromFilename

* Add new tests for name (and nameFromFilename)

* Add TypeScript for executableDir

* Start tests for subcommand search

* Comment-out unused routine for lint, WIP

* Refactor tests and skip launchable executable tests on Windows

* Add notes on further tests

* Filling out mock executable tests

* Expand tests

* Remove debugging and ToDo

* Relative and absolute test for executableDir

* Avoid memory leak warning

* Fix relative search test

* Separate and expand .name section in README.

And some lint, remove trailing spaces et al

* Add .name to multiple subcommand example

* Update description of executable search.

Add mention of .executableDir

* Add coverage of naming subcommands.

Readme.md

@@ -32,7 +32,8 @@ Read this in other languages: English | [简体中文](./Readme_zh-CN.md)
     - [Custom help](#custom-help)
     - [Display help after errors](#display-help-after-errors)
     - [Display help from code](#display-help-from-code)
-    - [.usage and .name](#usage-and-name)
+    - [.name](#name)
+    - [.usage](#usage)
     - [.helpOption(flags, description)](#helpoptionflags-description)
     - [.addHelpCommand()](#addhelpcommand)
     - [More configuration](#more-configuration-2)
@@ -66,15 +67,13 @@ This is used in the examples in this README for brevity.
 
 ```js
 const { program } = require('commander');
-program.version('0.0.1');
 ```
 
 For larger programs which may use commander in multiple ways, including unit testing, it is better to create a local Command object to use.
 
 ```js
 const { Command } = require('commander');
 const program = new Command();
-program.version('0.0.1');
 ```
 
 For named imports in ECMAScript modules, import from `commander/esm.mjs`.
@@ -93,7 +92,6 @@ import { Command } from 'commander';
 const program = new Command();
 ```
 
-
 ## Options
 
 Options are defined with the `.option()` method, also serving as documentation for the options. Each option can have a short flag (single character) and a long name, separated by a comma or space or vertical bar ('|').
@@ -550,15 +548,17 @@ pass more arguments than declared, but you can make this an error with `.allowEx
 ### Stand-alone executable (sub)commands
 
 When `.command()` is invoked with a description argument, this tells Commander that you're going to use stand-alone executables for subcommands.
-Commander will search the executables in the directory of the entry script (like `./examples/pm`) with the name `program-subcommand`, like `pm-install`, `pm-search`.
-You can specify a custom name with the `executableFile` configuration option.
+Commander will search the files in the directory of the entry script for a file with the name combination `command-subcommand`, like `pm-install` or `pm-search` in the example below. The search includes trying common file extensions, like `.js`.
+You may specify a custom name (and path) with the `executableFile` configuration option.
+You may specify a custom search directory for subcommands with `.executableDir()`.
 
 You handle the options for an executable (sub)command in the executable, and don't declare them at the top-level.
 
 Example file: [pm](./examples/pm)
 
 ```js
 program
+  .name('pm')
   .version('0.1.0')
   .command('install [name]', 'install one or more packages')
   .command('search [query]', 'search with optional query')
@@ -696,10 +696,25 @@ error: unknown option '--unknown'
 
 `.helpInformation()`: get the built-in command help information as a string for processing or displaying yourself.
 
-### .usage and .name
+### .name
 
-These allow you to customise the usage description in the first line of the help. The name is otherwise
-deduced from the (full) program arguments. Given:
+The command name appears in the help, and is also used for locating stand-alone executable subcommands.
+
+You may specify the program name using `.name()` or in the Command constructor. For the program, Commander will
+fallback to using the script name from the full arguments passed into `.parse()`. However, the script name varies
+depending on how your program is launched so you may wish to specify it explicitly.
+
+```js
+program.name('pizza');
+const pm = new Command('pm');
+```
+
+Subcommands get a name when specified using `.command()`. If you create the subcommand yourself to use with `.addCommand()`,
+then set the name using `.name()` or in the Command constructor.
+
+### .usage
+
+This allows you to customise the usage description in the first line of the help. Given:
 
 ```js
 program
@@ -715,7 +730,7 @@ Usage: my-command [global options] command
 
 ### .helpOption(flags, description)
 
-By default every command has a help option. Override the default help flags and description. Pass false to disable the built-in help option.
+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.
 
 ```js
 program
@@ -903,7 +918,6 @@ You can modify this behaviour for custom applications. In addition, you can modi
 
 Example file: [configure-output.js](./examples/configure-output.js)
 
-
 ```js
 function errorColor(str) {
   // Add ANSI escape codes to display text in red.
@@ -960,6 +974,7 @@ const { Command } = require('commander');
 const program = new Command();
 
 program
+  .name('deploy')
   .version('0.0.1')
   .option('-c, --config <path>', 'set config path', './deploy.conf');
 

Readme_zh-CN.md

@@ -65,15 +65,13 @@ npm install commander
 
 ```js
 const { program } = require('commander');
-program.version('0.0.1');
 ```
 
 如果程序较为复杂，用户需要以多种方式来使用 Commander，如单元测试等。创建本地`Command`对象是一种更好的方式：
 
 ```js
 const { Command } = require('commander');
 const program = new Command();
-program.version('0.0.1');
 ```
 
 要在 ECMAScript 模块中使用命名导入，可从`commander/esm.mjs`中导入。
@@ -270,6 +268,7 @@ $ collect --letter -n 1 -n 2 3 -- operand
 Options:  { number: [ '1', '2', '3' ], letter: true }
 Remaining arguments:  [ 'operand' ]
 ```
+
 关于可能有歧义的用例，请见[可变参数的选项](./docs/zh-CN/%E5%8F%AF%E5%8F%98%E5%8F%82%E6%95%B0%E7%9A%84%E9%80%89%E9%A1%B9.md)。
 
 ### 版本选项
@@ -534,6 +533,7 @@ Commander 将会尝试在入口脚本（例如`./examples/pm`）的目录中搜
 
 ```js
 program
+  .name('pm')
   .version('0.1.0')
   .command('install [name]', 'install one or more packages')
   .command('search [query]', 'search with optional query')
@@ -708,6 +708,7 @@ program.addHelpCommand('assist [command]', 'show assistance');
 内建帮助信息通过`Help`类进行格式化。如有需要，可以使用`.configureHelp()`来更改其数据属性和方法，或使用`.createHelp()`来创建子类，从而配置`Help`类的行为。
 
 数据属性包括：
+
 - `helpWidth`：指明帮助信息的宽度。可在单元测试中使用。
 - `sortSubcommands`：以字母序排列子命令
 - `sortOptions`：以字母序排列选项
@@ -862,7 +863,6 @@ Commander 默认用作命令行应用，其输出写入 stdout 和 stderr。
 
 示例代码：[configure-output.js](./examples/configure-output.js)
 
-
 ```js
 function errorColor(str) {
   // 添加 ANSI 转义字符，以将文本输出为红色
@@ -919,6 +919,7 @@ const { Command } = require('commander');
 const program = new Command();
 
 program
+  .name('deploy')
   .version('0.0.1')
   .option('-c, --config <path>', 'set config path', './deploy.conf');
 

examples/deploy

@@ -5,6 +5,7 @@ const { Command } = require('../'); // include commander in git clone of command
 const program = new Command();
 
 program
+  .name('deploy')
   .version('0.0.1')
   .option('-c, --config <path>', 'set config path', './deploy.conf');
 

examples/pm

@@ -5,6 +5,7 @@ const { Command } = require('../'); // include commander in git clone of command
 const program = new Command();
 
 program
+  .name('pm')
   .version('0.0.1')
   .description('Fake package manager')
   .command('install [name]', 'install one or more packages').alias('i')

examples/pm-install

@@ -17,7 +17,7 @@ if (!pkgs.length) {
 }
 
 console.log();
-if (program.force) console.log('  force: install');
+if (program.opts().force) console.log('  force: install');
 pkgs.forEach(function(pkg) {
   console.log('  install : %s', pkg);
 });