Store help option instance instead of just flags

Analogous to 3c94dfd in tj#1933 for version option.

Storing the Option instance of the help option instead of just its
flags (_helpShortFlag, _helpLongFlag) is meaningful for cases when other
properties of the instance need to be accessed (not currently the case,
but could be in the future).

lib/command.js

@@ -1099,7 +1099,7 @@ Expecting one of '${allowedValues.join("', '")}'`);
     }
 
     // Fallback to parsing the help flag to invoke the help.
-    return this._dispatchSubcommand(subcommandName, [], [this._helpLongFlag]);
+    return this._dispatchSubcommand(subcommandName, [], [this._helpOption.long]);
   }
 
   /**
@@ -2032,7 +2032,7 @@ Expecting one of '${allowedValues.join("', '")}'`);
     }
     context.write(helpInformation);
 
-    this.emit(this._helpLongFlag); // deprecated
+    this.emit(this._helpOption.long); // deprecated
     this.emit('afterHelp', context);
     getCommandAndParents(this).forEach(command => command.emit('afterAllHelp', context));
   }
@@ -2056,9 +2056,7 @@ Expecting one of '${allowedValues.join("', '")}'`);
     this._helpFlags = flags = flags || this._helpFlags;
     this._helpDescription = description = description || this._helpDescription;
 
-    const helpOption = this.createOption(flags, description);
-    this._helpShortFlag = helpOption.short;
-    this._helpLongFlag = helpOption.long;
+    this._helpOption = this.createOption(flags, description);
 
     return this;
   }
@@ -2123,7 +2121,7 @@ Expecting one of '${allowedValues.join("', '")}'`);
  */
 
 function outputHelpIfRequested(cmd, args) {
-  const helpOption = cmd._hasHelpOption && args.find(arg => arg === cmd._helpLongFlag || arg === cmd._helpShortFlag);
+  const helpOption = cmd._hasHelpOption && args.find(arg => arg === cmd._helpOption.long || arg === cmd._helpOption.short);
   if (helpOption) {
     cmd.outputHelp();
     // (Do not have all displayed text available so only passing placeholder.)

lib/help.js

@@ -71,14 +71,14 @@ class Help {
   visibleOptions(cmd) {
     const visibleOptions = cmd.options.filter((option) => !option.hidden);
     // Implicit help
-    const showShortHelpFlag = cmd._hasHelpOption && cmd._helpShortFlag && !cmd._findOption(cmd._helpShortFlag);
-    const showLongHelpFlag = cmd._hasHelpOption && !cmd._findOption(cmd._helpLongFlag);
+    const showShortHelpFlag = cmd._hasHelpOption && cmd._helpOption.short && !cmd._findOption(cmd._helpOption.short);
+    const showLongHelpFlag = cmd._hasHelpOption && !cmd._findOption(cmd._helpOption.long);
     if (showShortHelpFlag || showLongHelpFlag) {
       let helpOption;
       if (!showShortHelpFlag) {
-        helpOption = cmd.createOption(cmd._helpLongFlag, cmd._helpDescription);
+        helpOption = cmd.createOption(cmd._helpOption.long, cmd._helpDescription);
       } else if (!showLongHelpFlag) {
-        helpOption = cmd.createOption(cmd._helpShortFlag, cmd._helpDescription);
+        helpOption = cmd.createOption(cmd._helpOption.short, cmd._helpDescription);
       } else {
         helpOption = cmd.createOption(cmd._helpFlags, cmd._helpDescription);
       }

tests/command.copySettings.test.js

@@ -46,8 +46,8 @@ describe('copyInheritedSettings property tests', () => {
     cmd.copyInheritedSettings(source);
     expect(cmd._helpFlags).toBe('-Z, --zz');
     expect(cmd._helpDescription).toBe('ddd');
-    expect(cmd._helpShortFlag).toBe('-Z');
-    expect(cmd._helpLongFlag).toBe('--zz');
+    expect(cmd._helpOption.short).toBe('-Z');
+    expect(cmd._helpOption.long).toBe('--zz');
   });
 
   test('when copyInheritedSettings then copies addHelpCommand(name, description)', () => {