Add a full blown Graph

graph/Graph3.js

@@ -0,0 +1,101 @@
+class Node {
+  constructor(value) {
+    this.value = value;
+    this.adjecents = new Set();
+  }
+
+  removeAdjacent(node) {
+    return this.adjecents.delete(node);
+  }
+
+  addAdjacent(node) {
+    return this.adjecents.add(node);
+  }
+
+  isAdjacent(node) {
+    return this.adjecents.has(node);
+  }
+}
+
+class Graph {
+  constructor(edgeDirection = Graph.UNDIRECTED) {
+    this.nodes = new Map();
+    this.edgeDirection = edgeDirection;
+  }
+
+  addVertex(value) {
+    if (this.nodes.has(value)) {
+      return this.nodes.get(value);
+    }
+
+    const vertex = new Node(value);
+    this.nodes.set(value, vertex);
+    return vertex;
+  }
+
+  removeVertex(value) {
+    const current = this.nodes.get(value);
+    if (current) {
+      Array.from(this.nodes.values()).forEach((node) =>
+        node.removeAdjacent(current)
+      );
+    }
+
+    return this.nodes.delete(value);
+  }
+
+  addEdge(source, destination) {
+    const sourceNode = this.addVertex(source);
+    const destinationNode = this.addVertex(destination);
+
+    sourceNode.addAdjacent(destinationNode);
+
+    if (this.edgeDirection === Graph.UNDIRECTED) {
+      destinationNode.addAdjacent(sourceNode);
+    }
+
+    return [sourceNode, destinationNode];
+  }
+
+  removeEdge(source, destination) {
+    const sourceNode = this.nodes.get(source);
+    const destinationNode = this.nodes.get(destination);
+
+    if (sourceNode && destinationNode) {
+      sourceNode.removeAdjacent(destinationNode);
+
+      if (Graph.edgeDirection === Graph.UNDIRECTED) {
+        destinationNode.removeAdjacent(sourceNode);
+      }
+    }
+
+    return [sourceNode, destinationNode];
+  }
+
+  areAdjacent(source, destination) {
+    const sourceNode = this.nodes.get(source);
+    const destinationNode = this.nodes.get(destination);
+
+    if (sourceNode && destinationNode) {
+      return sourceNode.isAdjacent(destinationNode);
+    }
+
+    return false;
+  }
+}
+
+Graph.UNDIRECTED = Symbol("undirected graph"); // two-way edges
+Graph.DIRECTED = Symbol("directed graph"); // one-way edges
+
+const g1 = new Graph();
+g1.addVertex("bing");
+g1.addVertex("google");
+g1.addVertex("duck");
+g1.addVertex("aws");
+
+g1.addEdge("bing", "google");
+g1.addEdge("bing", "aws");
+
+console.log(g1);
+
+console.log(g1.areAdjacent("google", "bing"));