Design Patterns MCP Server

{ "id": "eager-loading", "name": "Eager Loading", "category": "Data Access", "description": "Loads related data upfront to avoid multiple database queries", "when_to_use": "Known data requirements\nQuery optimization\nReducing database calls", "benefits": "Fewer database calls\nPredictable performance\nSimple implementation", "drawbacks": "Memory overhead\nPotential over-fetching\nComplex queries", "use_cases": "Known access patterns\nPerformance optimization\nReporting systems", "complexity": "Medium", "tags": [ "data-access", "optimization", "loading" ], "examples": { "typescript": { "language": "typescript", "code": "// Eager Loading: load related data upfront\nclass User {\n constructor(\n public id: string,\n public email: string,\n public posts: Post[]\n ) {}\n}\n\nclass UserRepository {\n async findByIdWithPosts(id: string): Promise<User> {\n const userRow = await db.query('SELECT * FROM users WHERE id = $1', [id]);\n const postRows = await db.query('SELECT * FROM posts WHERE user_id = $1', [id]);\n \n return new User(\n userRow.id,\n userRow.email,\n postRows.map(p => ({ id: p.id, title: p.title }))\n );\n }\n \n async findAllWithPosts(): Promise<User[]> {\n const query = \\`\n SELECT u.*, p.id as post_id, p.title as post_title\n FROM users u\n LEFT JOIN posts p ON u.id = p.user_id\n \\`;\n \n const rows = await db.query(query);\n return this.groupByUser(rows);\n }\n \n private groupByUser(rows: any[]): User[] {\n const userMap = new Map<string, User>();\n for (const row of rows) {\n if (!userMap.has(row.id)) {\n userMap.set(row.id, new User(row.id, row.email, []));\n }\n if (row.post_id) {\n userMap.get(row.id)!.posts.push({ id: row.post_id, title: row.post_title });\n }\n }\n return Array.from(userMap.values());\n }\n}\n\nconst user = await userRepo.findByIdWithPosts('123');\n// Posts already loaded\nconsole.log(user.posts);" } } }