/**
* Simple Dependency Injection Container
* Eliminates singleton pattern repetition across modules
*/
export type ServiceFactory<T = any> = () => T | Promise<T>;
export class DIContainer {
private services: Map<string, any> = new Map();
private factories: Map<string, ServiceFactory> = new Map();
private singletons: Map<string, boolean> = new Map();
/**
* Register a service factory
*/
register<T>(name: string, factory: ServiceFactory<T>, singleton: boolean = true): void {
this.factories.set(name, factory);
this.singletons.set(name, singleton);
if (singleton) {
this.services.delete(name); // Clear cached instance
}
}
/**
* Register an instance directly
*/
registerInstance<T>(name: string, instance: T): void {
this.services.set(name, instance);
this.singletons.set(name, true);
}
/**
* Get a service instance
*/
async get<T>(name: string): Promise<T> {
// Check if instance already exists
if (this.services.has(name)) {
return this.services.get(name);
}
// Get factory
const factory = this.factories.get(name);
if (!factory) {
throw new Error(`Service '${name}' not registered`);
}
// Create instance
const instance = await factory();
// Cache if singleton
if (this.singletons.get(name)) {
this.services.set(name, instance);
}
return instance;
}
/**
* Check if service is registered
*/
has(name: string): boolean {
return this.factories.has(name) || this.services.has(name);
}
/**
* Clear a service instance (useful for testing or refresh)
*/
clear(name?: string): void {
if (name) {
this.services.delete(name);
} else {
this.services.clear();
}
}
/**
* Get all registered service names
*/
getRegisteredServices(): string[] {
return Array.from(new Set([...this.factories.keys(), ...this.services.keys()]));
}
}
// Global container instance
export const container = new DIContainer();
/**
* Decorator for easy service registration
*/
export function Service(name?: string) {
return function <T extends { new (...args: any[]): {} }>(constructor: T) {
const serviceName = name || constructor.name;
container.register(serviceName, () => new constructor(), true);
return constructor;
};
}
/**
* Helper function to get service from global container
*/
export function getService<T>(name: string): Promise<T> {
return container.get<T>(name);
}
