Improve executable subcommand tracking (#1056)

* Track executables better

* Bump version for release

* Update dependencies

CHANGELOG.md

@@ -5,6 +5,16 @@ All notable changes to this project will be documented in this file.
 The format is based on [Keep a Changelog](http://keepachangelog.com/en/1.0.0/)
 and this project adheres to [Semantic Versioning](http://semver.org/spec/v2.0.0.html). (Format adopted after v3.0.0.)
 
+## [3.0.2] (2019-09-27)
+
+### Fixed
+
+* Improve tracking of executable subcommands.
+
+### Changed
+
+* update development dependencies
+
 ## [3.0.1] (2019-08-30)
 
 ### Added

index.js

@@ -97,7 +97,7 @@ Option.prototype.is = function(arg) {
 function Command(name) {
   this.commands = [];
   this.options = [];
-  this._execs = {};
+  this._execs = new Set();
   this._allowUnknownOption = false;
   this._args = [];
   this._name = name || '';
@@ -149,7 +149,7 @@ Command.prototype.command = function(nameAndArgs, actionOptsOrExecDesc, execOpts
   if (desc) {
     cmd.description(desc);
     this.executables = true;
-    this._execs[cmd._name] = true;
+    this._execs.add(cmd._name);
     if (opts.isDefault) this.defaultExecutable = cmd._name;
   }
   cmd._noHelp = !!opts.noHelp;
@@ -498,7 +498,7 @@ Command.prototype.parse = function(argv) {
     });
   }
 
-  if (this._execs[name] && typeof this._execs[name] !== 'function') {
+  if (this._execs.has(name)) {
     return this.executeSubCommand(argv, args, parsed.unknown, subCommand ? subCommand._executableFile : undefined);
   }