Add some comments to Flow and Subflow classes

packages/node_modules/@node-red/runtime/lib/nodes/flows/Subflow.js

@@ -22,8 +22,20 @@ const flowUtil = require("./util");
 
 var Log;
 
-
+/**
+ * This class represents a subflow - which is handled as a special type of Flow
+ */
 class Subflow extends Flow {
+
+    /**
+     * Create a Subflow object.
+     * This takes a subflow definition and instance node, creates a clone of the
+     * definition with unique ids applied and passes to the super class.
+     * @param {[type]} parent          [description]
+     * @param {[type]} globalFlow      [description]
+     * @param {[type]} subflowDef      [description]
+     * @param {[type]} subflowInstance [description]
+     */
     constructor(parent,globalFlow,subflowDef,subflowInstance) {
         // console.log(subflowDef);
         // console.log("CREATE SUBFLOW",subflowDef.id,subflowInstance.id);
@@ -80,6 +92,14 @@ class Subflow extends Flow {
         this.node_map = node_map;
     }
 
+    /**
+     * Start the subflow.
+     * This creates a subflow instance node to handle the inbound messages. It also
+     * rewires an subflow internal node that is connected to an output so it is connected
+     * to the parent flow nodes the subflow instance is wired to.
+     * @param  {[type]} diff [description]
+     * @return {[type]}      [description]
+     */
     start(diff) {
         var self = this;
         // Create a subflow node to accept inbound messages and route appropriately
@@ -169,17 +189,19 @@ class Subflow extends Flow {
                 }
             }
         }
-
         super.start(diff);
     }
-
-    stop(stopList,removedList) {
-        return super.stop(stopList,removedList);
-    }
 }
 
 
-
+/**
+ * Clone a node definition for use within a subflow instance.
+ * Give the node a new id and set its _alias property to record
+ * its association with the original node definition.
+ * @param  {[type]} subflowInstanceId [description]
+ * @param  {[type]} def               [description]
+ * @return {[type]}                   [description]
+ */
 function createNodeInSubflow(subflowInstanceId, def) {
     let node = clone(def);
     let nid = redUtil.generateId();