Make it possible to delete edge from graph vertex.

src/data-structures/graph/GraphVertex.js

@@ -9,10 +9,22 @@ export default class GraphVertex {
       throw new Error('Graph vertex must have a value');
     }
 
+    /**
+     * @param {GraphEdge} edgeA
+     * @param {GraphEdge} edgeB
+     */
+    const edgeComparator = (edgeA, edgeB) => {
+      if (edgeA.getKey() === edgeB.getKey()) {
+        return 0;
+      }
+
+      return edgeA.getKey() < edgeB.getKey() ? -1 : 1;
+    };
+
     // Normally you would store string value like vertex name.
     // But generally it may be any object as well
     this.value = value;
-    this.edges = new LinkedList();
+    this.edges = new LinkedList(edgeComparator);
   }
 
   /**
@@ -25,6 +37,13 @@ export default class GraphVertex {
     return this;
   }
 
+  /**
+   * @param {GraphEdge} edge
+   */
+  deleteEdge(edge) {
+    this.edges.delete(edge);
+  }
+
   /**
    * @returns {GraphVertex[]}
    */