Dependency Tree Visualization

This example demonstrates how to visualize and analyze dependency trees for services using getDependencyTree() and visualizeDependencyTree() methods.

Code

import { ServiceCollection } from '@nodelibraries/ioc';

// Register services with dependencies
const services = new ServiceCollection();
const IConfigToken = Symbol('IConfig');
const ILoggerToken = Symbol('ILogger');
const IDatabaseToken = Symbol('IDatabase');
const IUserRepositoryToken = Symbol('IUserRepository');
const IUserServiceToken = Symbol('IUserService');

services.addSingleton(IConfigToken, Config);
services.addSingleton(ILoggerToken, Logger);
services.addSingleton(IDatabaseToken, Database, [IConfigToken]);
services.addSingleton(IUserRepositoryToken, UserRepository, [IDatabaseToken, ILoggerToken]);
services.addSingleton(IUserServiceToken, UserService, [IUserRepositoryToken, ILoggerToken]);

// Visualize dependency tree
console.log(services.visualizeDependencyTree(IUserServiceToken));

// Get dependency tree as object
const tree = services.getDependencyTree(IUserServiceToken);
console.log(JSON.stringify(tree, null, 2));

Output

└── Symbol(IUserService) [SINGLETON]
    ├── Symbol(IUserRepository) [SINGLETON]
    │   ├── Symbol(IDatabase) [SINGLETON]
    │   │   └── Symbol(IConfig) [SINGLETON]
    │   └── Symbol(ILogger) [SINGLETON]
    └── Symbol(ILogger) [SINGLETON]

Methods

getDependencyTree(token: Token): DependencyTreeNode

Returns a tree structure showing all dependencies for a specific service token.

Returns:

• DependencyTreeNode object with:
  • token: The service token
  • name: Human-readable name
  • lifetime: Service lifetime (SINGLETON, SCOPED, TRANSIENT, CIRCULAR, NOT_REGISTERED)
  • dependencies: Array of dependency nodes
  • depth: Depth in the tree
  • isCircular: Whether this node is part of a circular dependency
  • circularPath: Path showing the circular dependency (if applicable)

visualizeDependencyTree(token: Token): string

Returns a formatted string representation of the dependency tree, suitable for console output.

Features

• Tree Visualization: See the complete dependency hierarchy
• Circular Detection: Automatically detects and marks circular dependencies
• Lifetime Information: Shows the lifetime of each service
• Object Structure: Get the tree as a structured object for programmatic use

Run This Example

npx ts-node examples/18-dependency-tree.ts

Full Example: Source Code