Cache children for already visited nodes

Author: twwd

src/lib/tree.spec.ts

@@ -0,0 +1,113 @@
+import { describe, it, expect } from 'vitest';
+import type { Bom } from '$lib/cyclonedx/models';
+import { type TreeItem, TreeItemImpl } from '$lib/models/tree';
+import { createTreeDataFromBom } from '$lib/tree';
+
+describe('createTreeDataFromBom', () => {
+	it('creates a tree structure from a basic BOM', () => {
+		const bom: Bom = {
+			metadata: {
+				component: {
+					'bom-ref': 'subject-ref',
+					name: 'subject-name',
+					type: 'application'
+				}
+			},
+			components: [
+				{
+					'bom-ref': 'a-ref',
+					type: 'library',
+					name: 'a-name'
+				},
+				{
+					'bom-ref': 'b-ref',
+					type: 'library',
+					name: 'b-name'
+				},
+				{
+					'bom-ref': 'c-ref',
+					type: 'library',
+					name: 'c-name'
+				},
+				{
+					'bom-ref': 'd-ref',
+					type: 'library',
+					name: 'd-name'
+				}
+			],
+			dependencies: [
+				{
+					ref: 'subject-ref',
+					dependsOn: ['a-ref', 'b-ref']
+				},
+				{
+					ref: 'a-ref',
+					dependsOn: ['c-ref', 'd-ref']
+				},
+				{
+					ref: 'b-ref',
+					dependsOn: []
+				},
+				{
+					ref: 'c-ref',
+					dependsOn: ['d-ref']
+				}
+			]
+		};
+
+		const expected: TreeItem[] = [
+			new TreeItemImpl('a-name', 'a-ref', [
+				new TreeItemImpl('c-name', 'c-ref', [new TreeItemImpl('d-name', 'd-ref')]),
+				new TreeItemImpl('d-name', 'd-ref')
+			]),
+			new TreeItemImpl('b-name', 'b-ref')
+		];
+
+		expect(createTreeDataFromBom(bom)).toStrictEqual(expected);
+	});
+	it('can handle cycles in the BOM dependencies', () => {
+		const bom: Bom = {
+			metadata: {
+				component: {
+					'bom-ref': 'subject-ref',
+					name: 'subject-name',
+					type: 'application'
+				}
+			},
+			components: [
+				{
+					'bom-ref': 'a-ref',
+					type: 'library',
+					name: 'a-name'
+				},
+				{
+					'bom-ref': 'b-ref',
+					type: 'library',
+					name: 'b-name'
+				}
+			],
+			dependencies: [
+				{
+					ref: 'subject-ref',
+					dependsOn: ['a-ref']
+				},
+				{
+					ref: 'a-ref',
+					dependsOn: ['b-ref']
+				},
+				{
+					ref: 'b-ref',
+					dependsOn: ['a-ref']
+				}
+			]
+		};
+
+		const expected: TreeItem[] = [
+			new TreeItemImpl('a-name', 'a-ref', [
+				new TreeItemImpl('b-name', 'b-ref', [new TreeItemImpl('a-name', 'a-ref')])
+			])
+		];
+
+		expect(createTreeDataFromBom(bom)).toStrictEqual(expected);
+	});
+});

src/lib/tree.ts

@@ -19,6 +19,8 @@ export function createTreeDataFromBom(bom: Bom): TreeItem[] {
 
 	const subject = bom.metadata?.component;
 
+	const childrenCache = new Map<string, TreeItem[] | undefined>();
+
 	function getChildTreeItems(componentRef: string, visited: Set<string>): TreeItem[] {
 		// If we've already visited this component, return an empty array to prevent cycles
 		if (visited.has(componentRef)) {
@@ -32,11 +34,14 @@ export function createTreeDataFromBom(bom: Bom): TreeItem[] {
 		return (dependencyMap.get(componentRef) ?? [])
 			.map((child) => {
 				if (componentRefToName.has(child)) {
-					return new TreeItemImpl(
-						componentRefToName.get(child)!,
-						child,
-						getChildTreeItems(child, new Set(visited))
-					);
+					let children;
+					if (childrenCache.has(child)) {
+						children = childrenCache.get(child);
+					} else {
+						children = getChildTreeItems(child, new Set(visited));
+						childrenCache.set(child, children);
+					}
+					return new TreeItemImpl(componentRefToName.get(child)!, child, children);
 				} else {
 					return null;
 				}