Use getCommandAndParents for array of parents (#1566)

Author: shadowspawn

lib/command.js

@@ -1662,14 +1662,7 @@ Expecting one of '${allowedValues.join("', '")}'`);
     }
     const context = this._getHelpContext(contextOptions);
 
-    const groupListeners = [];
-    let command = this;
-    while (command) {
-      groupListeners.push(command); // ordered from current command to root
-      command = command.parent;
-    }
-
-    groupListeners.slice().reverse().forEach(command => command.emit('beforeAllHelp', context));
+    getCommandAndParents(this).reverse().forEach(command => command.emit('beforeAllHelp', context));
     this.emit('beforeHelp', context);
 
     let helpInformation = this.helpInformation(context);
@@ -1683,7 +1676,7 @@ Expecting one of '${allowedValues.join("', '")}'`);
 
     this.emit(this._helpLongFlag); // deprecated
     this.emit('afterHelp', context);
-    groupListeners.forEach(command => command.emit('afterAllHelp', context));
+    getCommandAndParents(this).forEach(command => command.emit('afterAllHelp', context));
   };
 
   /**