Solution: Factory for Dynamically Composed Middleware Chains

Understand how to implement a middleware factory that dynamically composes a chain of middleware components based on runtime configuration. This lesson guides you through creating a pipeline that executes middleware in the configured order while maintaining modularity and flexibility in Node.js applications.

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Revisit the problem statement

Solution explanation

Lines 1–26: We define three middleware classes: LoggerMiddleware, AuthMiddleware, and RateLimitMiddleware.
- Each exposes an async .handle(req, next) method, modifying the request and then invoking next() to continue the chain.
- This shared interface ensures all middleware can be composed dynamically.
Lines 28–32: The middlewareMap object links config keys ('logger', 'auth', 'rateLimit') to their respective classes.
- This allows the factory to instantiate the correct middleware based on the config array without branching. ...

1.Introduction to Node.js Patterns

2.Factory Pattern: Generate Config-Driven Services Dynamically

3.Builder Pattern: Assemble Complex Objects with Fluent APIs

4.Decorator Pattern: Extend Behavior Without Modifying Core Logic

5.Adapter Pattern: Standardize Interface Across Dependencies

6.Proxy Pattern: Intercept and Control Access Transparently

7.Strategy Pattern: Swap Algorithms Based on Context

8.Wrapping Up

Solution: Factory for Dynamically Composed Middleware Chains

Solution explanation