refactor(menu): Made sure the menu can be used for more than group

source/Menu/MenuTraversal.ts

@@ -0,0 +1,105 @@
+import {AnyMenuItem, MenuItemType} from "./MenuRenderer.types";
+import {TraversalMap, StringifiedTraversalPath, TraversalPath, TraversalKey} from "./MenuTraversal.types";
+import {InvalidTraversalRouteError} from "./InvalidTraversalRouteError";
+
+export class MenuTraversal {
+  private readonly traversalMap: TraversalMap
+  private currentPath: TraversalPath = [];
+  
+  public get path() {
+    return this.currentPath;
+  }
+  
+  public get stringifiedPath(): StringifiedTraversalPath {
+    return this.stringifyTraversalPath(this.currentPath);
+  }
+  
+  public get currentMenuItem(): AnyMenuItem {
+    const path = this.stringifiedPath;
+    if (!this.traversalMap.has(path)) {
+      throw new InvalidTraversalRouteError(this.currentPath);
+    }
+    
+    return <AnyMenuItem>this.traversalMap.get(path);
+  }
+  
+  public get isRoot(): boolean {
+    return this.currentPath.length === 0;
+  }
+  
+  constructor(
+    private readonly menu: AnyMenuItem[],
+    private readonly rootLabel: string = "",
+    private readonly rootDescription: string = ''
+  ) {
+    this.traversalMap = this.generateTraversalMap();
+    
+  }
+  
+  public travelForward(next: TraversalKey) {
+    const nextPath = [
+      ...this.currentPath,
+      next
+    ];
+    
+    if (!this.traversalMap.has(this.stringifyTraversalPath(nextPath))) {
+      throw new InvalidTraversalRouteError(nextPath);
+    }
+    
+    this.currentPath = nextPath;
+  }
+  
+  public travelBack() {
+    this.currentPath.pop();
+  }
+  
+  public getMenuItem(path: StringifiedTraversalPath): AnyMenuItem 
+  {
+    if (!this.traversalMap.has(path)) {
+      throw new InvalidTraversalRouteError([path]);
+    }
+    
+    return <AnyMenuItem>this.traversalMap.get(path);
+  }
+  
+  public static unstringifyTraversalPath(path: StringifiedTraversalPath): TraversalPath {
+    return path.split('/');
+  }
+
+  private generateTraversalMap(): TraversalMap {
+    const map = new Map<StringifiedTraversalPath, AnyMenuItem>();
+
+    map.set('', {
+      traversalKey: '',
+      label: this.rootLabel,
+      description: this.rootDescription,
+      type: MenuItemType.Collection,
+      children: this.menu
+    });
+
+    const that = this;
+
+    function traversePath(path: TraversalPath, menuItem: AnyMenuItem) {
+      path = [...path, menuItem.traversalKey];
+      map.set(that.stringifyTraversalPath(path), menuItem);
+
+      if (menuItem.type !== MenuItemType.Collection) {
+        return;
+      }
+
+      menuItem.children.forEach((nextMenuItem) => {
+        traversePath(path, nextMenuItem);
+      })
+    }
+
+    this.menu.forEach((menuItem) => {
+      traversePath([], menuItem);
+    })
+
+    return map;
+  }
+  
+  private stringifyTraversalPath(path: TraversalPath): StringifiedTraversalPath {
+    return path.join('/');
+  }
+}