feat: implement Tree

modules/@angular/router/src/tree.ts

@@ -0,0 +1,69 @@
+export class Tree<T> {
+  /** @internal */
+  _root: TreeNode<T>;
+
+  constructor(root: TreeNode<T>) { this._root = root; }
+
+  get root(): T { return this._root.value; }
+
+  parent(t: T): T {
+    const p = this.pathFromRoot(t);
+    return p.length > 1 ? p[p.length - 2] : null;
+  }
+
+  children(t: T): T[] {
+    const n = _findNode(t, this._root);
+    return n ? n.children.map(t => t.value) : null;
+  }
+
+  firstChild(t: T): T {
+    const n = _findNode(t, this._root);
+    return n && n.children.length > 0 ? n.children[0].value : null;
+  }
+
+  pathFromRoot(t: T): T[] { return _findPath(t, this._root, []).map(s => s.value); }
+
+  contains(tree: Tree<T>): boolean { return _contains(this._root, tree._root); }
+}
+
+export function rootNode<T>(tree: Tree<T>): TreeNode<T> {
+  return tree._root;
+}
+
+function _findNode<T>(expected: T, c: TreeNode<T>): TreeNode<T> {
+  if (expected === c.value) return c;
+  for (let cc of c.children) {
+    const r = _findNode(expected, cc);
+    if (r) return r;
+  }
+  return null;
+}
+
+function _findPath<T>(expected: T, c: TreeNode<T>, collected: TreeNode<T>[]): TreeNode<T>[] {
+  collected.push(c);
+  if (expected === c.value) return collected;
+
+  for (let cc of c.children) {
+    const cloned = collected.slice(0);
+    const r = _findPath(expected, cc, cloned);
+    if (r) return r;
+  }
+
+  return null;
+}
+
+function _contains<T>(tree: TreeNode<T>, subtree: TreeNode<T>): boolean {
+  if (tree.value !== subtree.value) return false;
+
+  for (let subtreeNode of subtree.children) {
+    const s = tree.children.filter(child => child.value === subtreeNode.value);
+    if (s.length === 0) return false;
+    if (!_contains(s[0], subtreeNode)) return false;
+  }
+
+  return true;
+}
+
+export class TreeNode<T> {
+  constructor(public value: T, public children: TreeNode<T>[]) {}
+}

modules/@angular/router/test/tree.spec.ts

@@ -0,0 +1,50 @@
+import {Tree, TreeNode} from '../src/tree';
+
+describe('tree', () => {
+  it("should return the root of the tree", () => {
+    const t = new Tree<any>(new TreeNode<number>(1, []));
+    expect(t.root).toEqual(1);
+  });
+
+  it("should return the parent of a node", () => {
+    const t = new Tree<any>(new TreeNode<number>(1, [new TreeNode<number>(2, [])]));
+    expect(t.parent(1)).toEqual(null);
+    expect(t.parent(2)).toEqual(1);
+  });
+
+  it("should return the children of a node", () => {
+    const t = new Tree<any>(new TreeNode<number>(1, [new TreeNode<number>(2, [])]));
+    expect(t.children(1)).toEqual([2]);
+    expect(t.children(2)).toEqual([]);
+  });
+
+  it("should return the first child of a node", () => {
+    const t = new Tree<any>(new TreeNode<number>(1, [new TreeNode<number>(2, [])]));
+    expect(t.firstChild(1)).toEqual(2);
+    expect(t.firstChild(2)).toEqual(null);
+  });
+
+  it("should return the path to the root", () => {
+    const t = new Tree<any>(new TreeNode<number>(1, [new TreeNode<number>(2, [])]));
+    expect(t.pathFromRoot(2)).toEqual([1, 2]);
+  });
+
+  describe("contains", () => {
+    it("should work", () => {
+      const tree = new Tree<any>(
+        new TreeNode<number>(1, [new TreeNode<number>(2, []), new TreeNode<number>(3, [])]));
+      const subtree1 = new Tree<any>(new TreeNode<number>(1, []));
+      const subtree2 = new Tree<any>(new TreeNode<number>(1, [new TreeNode<number>(2, [])]));
+      const subtree3 = new Tree<any>(new TreeNode<number>(1, [new TreeNode<number>(3, [])]));
+      const notSubtree1 = new Tree<any>(new TreeNode<number>(1, [new TreeNode<number>(4, [])]));
+      const notSubtree2 = new Tree<any>(
+        new TreeNode<number>(1, [new TreeNode<number>(2, [new TreeNode<number>(4, [])])]));
+
+      expect(tree.contains(subtree1)).toEqual(true);
+      expect(tree.contains(subtree2)).toEqual(true);
+      expect(tree.contains(subtree3)).toEqual(true);
+      expect(tree.contains(notSubtree1)).toEqual(false);
+      expect(tree.contains(notSubtree2)).toEqual(false);
+    });
+  });
+});

modules/@angular/router/tsconfig.json

@@ -14,6 +14,7 @@
   },
   "files": [
     "src/router.ts",
+    "test/tree.spec.ts",
     "test/router.spec.ts",
     "typings/main.d.ts"
   ]