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Generic Repository Interface

Define a repository contract parameterised by entity and id type, so different stores share one shape without duplicating method signatures.

TypescriptData Integrity

Code

snippet
export interface Entity {
  id: string;
}

export interface Repository<T extends Entity, Id = string> {
  findById(id: Id): Promise<T | null>;
  findAll(): Promise<T[]>;
  save(entity: T): Promise<T>;
  delete(id: Id): Promise<boolean>;
}

export class InMemoryRepository<T extends Entity> implements Repository<T> {
  private store = new Map<string, T>();

  async findById(id: string): Promise<T | null> {
    return this.store.get(id) ?? null;
  }

  async findAll(): Promise<T[]> {
    return [...this.store.values()];
  }

  async save(entity: T): Promise<T> {
    this.store.set(entity.id, entity);
    return entity;
  }

  async delete(id: string): Promise<boolean> {
    return this.store.delete(id);
  }
}

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