graph_editor: support re-rendering graph

This is required with ERP5JS, where every save call render with new data.

bt5/erp5_graph_editor/SkinTemplateItem/portal_skins/erp5_graph_editor/dream_graph_editor/jsplumb/jsplumb.js.js

@@ -225,8 +225,8 @@
 
     function updateConnectionData(gadget, connection, remove) {
         if (connection.ignoreEvent) {
-            // this hack is for edge edition. Maybe there I missed one thing and
-            // there is a better way.
+            // this hack is for edge edition and when the graph is re-rendered.
+            // Maybe there I missed one thing and there is a better way.
             return;
         }
         if (remove) {
@@ -815,6 +815,20 @@
            }
          });
         */
+
+            // reset previous graph, if any.
+            if ($(".window", this.props.element).length) {
+                $.each(
+                    // disable the "delete" event, otherwise after render load the
+                    // graph, loopJsplumbBind events will process the connection deleted
+                    // events 
+                    this.props.jsplumb_instance.getAllConnections(),
+                    function (i, connection) {
+                        connection.ignoreEvent = true;
+                    });
+                this.props.jsplumb_instance.reset();
+                $(".window", this.props.element).remove();
+            }
             if (data) {
                 this.props.data = JSON.parse(data);
 

bt5/erp5_graph_editor/SkinTemplateItem/portal_skins/erp5_graph_editor/dream_graph_editor/jsplumb/test.js.js

@@ -591,5 +591,24 @@
                 });
             }).fail(error_handler).always(start);
         });
+        test("Gadget can be rendered multiple times", function () {
+            var jsplumb_gadget;
+            stop();
+            g.declareGadget("./index.html", {
+                element: document.querySelector("#test-element")
+            }).then(function (new_gadget) {
+                jsplumb_gadget = new_gadget;
+                return jsplumb_gadget.render(sample_data_graph);
+            }).then(function () {
+                return jsplumb_gadget.getContent();
+            }).then(function () {
+                return jsplumb_gadget.render(sample_data_graph);
+            }).then(function () {
+                return jsplumb_gadget.getContent();
+            }).then(function (content) {
+                equal(sample_data_graph, content);
+                equal($(".window", document.querySelector("#test-element")).length, 2, "Graph is rendered only once");
+            }).fail(error_handler).always(start);
+        });
     });
 }(rJS, JSON, QUnit, RSVP, jQuery));
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