create road module

Author: pldvd

chapter_eight_road_module.js

@@ -0,0 +1,15 @@
+const buildGraph = require('./chapter_seven_robot_project');
+
+const roads = [
+  "Alice's House-Bob's House",   "Alice's House-Cabin",
+  "Alice's House-Post Office",   "Bob's House-Town Hall",
+  "Daria's House-Ernie's House", "Daria's House-Town Hall",
+  "Ernie's House-Grete's House", "Grete's House-Farm",
+  "Grete's House-Shop",          "Marketplace-Farm",
+  "Marketplace-Post Office",     "Marketplace-Shop",
+  "Marketplace-Town Hall",       "Shop-Town Hall"
+];
+
+const roadGraph = buildGraph(roads);
+
+module.exports = roadGraph;

chapter_seven_robot_project.js

@@ -11,7 +11,7 @@ const roads = [
   "Marketplace-Town Hall", "Shop-Town Hall"
 ];
 
-function buildGraph(from, to) {
+const buildGraph = function(from, to) {
   let graph = Object.create(null);
   function addEdge(from, to) {
     if (!graph[from]) {
@@ -185,4 +185,6 @@ console.log(b.has("b"));
 console.log(a.has("b"));
 // → false
 console.log(b.has("a"));
-// → false
+// → false
+
+module.exports = buildGraph;