Save and recall expansion state of tree

- Save choices to sessionStorage

InvenTree/InvenTree/views.py

@@ -21,7 +21,11 @@ from rest_framework import views
 
 
 class TreeSerializer(views.APIView):
-    """ JSON View for serializing a Tree object.
+    """ JSON View for serializing a Tree object. 
+
+    Turns a 'tree' model into a JSON object compatible with bootstrap-treview.
+
+    Ref: https://github.com/jonmiles/bootstrap-treeview
     """
 
     def itemToJson(self, item):

InvenTree/static/script/inventree/sidenav.js

@@ -11,6 +11,29 @@ function loadTree(url, tree, data) {
                     data: response.tree,
                     enableLinks: true
                 });
+
+                var saved_exp = sessionStorage.getItem('inventree-sidenav-expanded-items').split(",");
+
+                // Automatically expand the desired notes
+                for (var q = 0; q < saved_exp.length; q++) {
+                    $(tree).treeview('expandNode', parseInt(saved_exp[q]));
+                }
+
+                // Setup a callback whenever a node is toggled
+                $(tree).on('nodeExpanded nodeCollapsed', function(event, data) {
+                    
+                    // Record the entire list of expanded items
+                    var expanded = $(tree).treeview('getExpanded');
+
+                    var exp = [];
+
+                    for (var i = 0; i < expanded.length; i++) {
+                        exp.push(expanded[i].nodeId);
+                    }
+
+                    // Save the expanded nodes
+                    sessionStorage.setItem('inventree-sidenav-expanded-items', exp);
+                });
             }
         },
         error: function (xhr, ajaxOptions, thrownError) {
@@ -24,6 +47,8 @@ function openSideNav() {
     document.getElementById("inventree-content").style.marginLeft = "270px";
 
     sessionStorage.setItem('inventree-sidenav-state', 'open');
+
+
 }
 
 function closeSideNav() {