Implemented basic toString

src/editor/js/structures/graph/link.ts

@@ -101,4 +101,16 @@ export class Link extends GraphElement {
 
         return link;
     }
+
+    public toString(): string {
+        let source: any = this.source;
+        let target: any = this.target;
+
+        if (this.source == undefined || this.target == undefined) {
+            source = this.sourceId;
+            target = this.targetId;
+        }
+        
+        return source.toString() + " -> " + target.toString();
+    }
 }

src/editor/js/structures/graph/node.ts

@@ -101,4 +101,8 @@ export class Node extends GraphElement {
 
         return node;
     }
+
+    public toString(): string {
+        return this.label;
+    }
 }