feat: add circular reference to parents of nodes

npm/ng-packs/packages/core/src/lib/tests/tree-utils.spec.ts

@@ -1,4 +1,4 @@
-import { createTreeFromList, TreeNode } from '../utils/tree-utils';
+import { BaseTreeNode, createTreeFromList, TreeNode } from '../utils/tree-utils';
 
 const LIST_1 = [
   { id: 1, pid: null },
@@ -46,23 +46,32 @@ describe('Tree Utils', () => {
       ${LIST_2} | ${TREE_2}
       ${LIST_3} | ${TREE_3}
     `('should return $expected when given $list', ({ list, expected }: TestCreateTreeFromList) => {
-      expect(
-        createTreeFromList(
-          list,
-          x => x.id,
-          x => x.pid,
-        ),
-      ).toEqual(expected);
+      const tree = createTreeFromList(
+        list,
+        x => x.id,
+        x => x.pid,
+        x => BaseTreeNode.create(x),
+      );
+
+      expect(removeParents(tree)).toEqual(expected);
     });
   });
 });
 
+function removeParents(tree: TreeNode<Model>[]) {
+  return tree.map(v => {
+    const { parent, ...node } = v;
+    node.children = removeParents(node.children);
+    return node;
+  });
+}
+
 interface TestCreateTreeFromList {
-  list: ModelA[];
-  expected: TreeNode<ModelA>[];
+  list: Model[];
+  expected: TreeNode<Model>[];
 }
 
-interface ModelA {
+interface Model {
   id: 1;
   pid: null;
 }

npm/ng-packs/packages/core/src/lib/utils/tree-utils.ts

@@ -1,19 +1,20 @@
-export class TreeNodeFactory<T extends object> {
+export class BaseTreeNode<T extends object> {
   children: TreeNode<T>[] = [];
   isLeaf = true;
+  parent: TreeNode<T>;
 
   constructor(props: T) {
     Object.assign(this, props);
   }
 
   static create<T extends object>(props: T) {
-    return new TreeNodeFactory<T>(props) as TreeNode<T>;
+    return new BaseTreeNode<T>(props) as TreeNode<T>;
   }
 }
 
 export function createTreeFromList<T extends object, R extends unknown>(
   list: T[],
-  keySelector: (item: T) => number | string | Symbol,
+  keySelector: (item: T) => number | string | symbol,
   parentKeySelector: typeof keySelector,
   valueMapper: (item: T) => R,
 ) {
@@ -27,8 +28,10 @@ export function createTreeFromList<T extends object, R extends unknown>(
 
     if (parentId) {
       const parent = map.get(parentId);
+      if (!parent) return;
       (parent as any).children.push(node);
       (parent as any).isLeaf = false;
+      (node as any).parent = parent;
     } else {
       tree.push(node);
     }
@@ -39,7 +42,7 @@ export function createTreeFromList<T extends object, R extends unknown>(
 
 export function createMapFromList<T extends object, R extends unknown>(
   list: T[],
-  keySelector: (item: T) => number | string | Symbol,
+  keySelector: (item: T) => number | string | symbol,
   valueMapper: (item: T) => R,
 ) {
   type Key = ReturnType<typeof keySelector>;
@@ -54,6 +57,7 @@ export type TreeNode<T extends object> = {
 } & {
   children: TreeNode<T>[];
   isLeaf: boolean;
+  parent?: TreeNode<T>;
 };
 
 type NodeValue<T extends object, F extends (...args: any) => any> = F extends undefined