Hybrid Approach: A New Way of Structuring Your Node.js Projects
Tags: javascript, node, programming, architecture
Published: 2021-03-22 21:52:43

#

"Innovative Techniques to Boost Productivity and Maintainability in Node.js Development

# Introduction

### Purpose of the document

This document discusses a new architecture intended for backend development, supporting Node.js, ES6, and TypeScript.

### Overview

In today's fast-paced modern world, projects need to be developed quickly, adaptable to new requirements, and ready for scalability. However, it is not an easy task for developers to maintain high-quality code and keep everything organized. 


To address these issues and maintain a clean project structure, it is important to follow a specific architecture. However, have the proposed architectures solved the issues? No, as we still face daily problems. Project complexity increases with new requirements, and files become lengthy. Therefore, we need a project design that effectively handles these issues. but How? 

# ****Architecture Overview****

### The Hybrid approach

The Hybrid Approach is a software development methodology that combines the strengths of different architectural patterns and design principles to create a flexible and organized codebase. It's like having the best of both worlds in structuring a Node.js project.
The Hybrid Approach shines when you have projects with diverse components and requirements, like APIs, pub/sub logic, workflows, retry mechanisms, and algorithms...

### Project Structure

let's explore how a CRUD (Create, Read, Update, Delete) application for managing cars can be structured using the Hybrid Approach. In this example, we'll emphasize that each operation has its own business logic. Here's the directory structure:

project-root/
|-- src/
|   |-- cars/
|   |   |-- cars.controller.ts
|   |   |-- internal/
|   |   |   |-- cars.model.ts
|   |   |   |-- cars.types.ts
|   |   |   |-- createCar.service.ts
|   |   |   |-- readCar.service.ts
|   |   |   |-- updateCar.service.ts
|   |   |   |-- deleteCar.service.ts
|-- app.ts
|-- package.json
|-- tsconfig.json
|-- [README.md](http://readme.md/)

- **`cars/`** is the directory representing the feature for managing cars.
- Inside the **`cars/`** directory:
    - **`cars.controller.ts`** handles routing and request handling for car-related operations.
    - The **`internal/`** subdirectory contains feature-specific details:
        - **`cars.model.ts`** defines the data model or schema for car records, specifying details like make, model, and VIN.
        - **`cars.types.ts`** includes types or interfaces related to cars for type checking and data consistency also enums
        - **`createCar.service.ts`** contains the service logic for creating new car entries. This logic might include uniqueness checks for the VIN and initial sale price calculations.
        - **`readCar.service.ts`** manages the logic for reading car details, which might involve retrieving data from the database and applying specific filters or transformations.
        - **`updateCar.service.ts`** handles the logic for updating car records, including business rules for depreciation calculations or price adjustments.
        - **`deleteCar.service.ts`** contains the logic for deleting car records, which may involve additional checks or notifications.

```jsx
// createCar.service.ts

import { CarModel } from './cars.model';
import { Car } from './cars.types';

// Main function to consolidate logic and create a new car entry
async function main(newCarData: Car): Promise<Car> {
  // Implement business logic here
  // For example, check if the VIN is unique
  const isUniqueVIN = await isVINUnique(newCarData.VIN);

  if (!isUniqueVIN) {
    throw new Error('A car with the same VIN already exists.');
  }

  // Calculate initial sale price based on make and model
  const initialSalePrice = calculateInitialSalePrice(newCarData.make, newCarData.model);

  // Create the new car entry
  const createdCar = await CarModel.create({
    ...newCarData,
    initialSalePrice,
  });

  return createdCar;
}
// Function to check if the VIN is unique
async function isVINUnique(VIN: string): Promise<boolean> {
  // Implement logic to check VIN uniqueness in the database
}

// Function to calculate initial sale price
function calculateInitialSalePrice(make: string, model: string): number {
  // Implement pricing logic based on make and model
}

export { main };
```

 Let's consider a project with significant business logic and multiple dependencies that doesn't involve CRUD operations. We'll use an example of an e-commerce recommendation engine. This system suggests products to users based on their preferences and behavior. Here's how you can model it with the Hybrid Approach:

**Project Structure:**

```
plaintextCopy code
project-root/
|-- src/
|   |-- recommendation/
|   |   |-- recommendation.controller.ts
|   |   |-- internal/
|   |   |   |-- recommendation.model.ts
|   |   |   |-- recommendation.types.ts
|   |   |   |-- userPreferences.service.ts
|   |   |   |-- behaviorAnalyzer.service.ts
|   |   |   |-- recommendationEngine.service.ts
|-- app.ts
|-- package.json
|-- tsconfig.json
|-- README.md

```

**Key Principles:**

1. **Modular Organization**: The codebase is divided into feature-specific modules. In this case, the "recommendation" feature focuses on product recommendations.
2. **Clear Separation of Concerns**: Within the "recommendation" feature:
    - **`recommendation.controller.ts`**: Manages routing for recommendation-related requests.
    - **`internal/`** subdirectory: Contains feature-specific components:
        - **`recommendation.model.ts`**: Defines the data model or schema for recommendation records (if needed).
        - **`recommendation.types.ts`**: Includes types or interfaces for recommendations.
        - **`userPreferences.service.ts`**: Manages user preferences and interactions with the system.
        - **`behaviorAnalyzer.service.ts`**: Analyzes user behavior and identifies patterns.
        - **`recommendationEngine.service.ts`**: Implements the core recommendation logic based on preferences and behavior.

**Service Logic Example (recommendationEngine.service.ts):**

```tsx
typescriptCopy code
// recommendationEngine.service.ts

import { UserPreferences, BehaviorData, Recommendation } from './recommendation.types';
import { UserPreferencesService } from './userPreferences.service';
import { BehaviorAnalyzerService } from './behaviorAnalyzer.service';

// Main function to consolidate logic for generating recommendations
async function main(userId: string): Promise<Recommendation[]> {
  // Implement the core recommendation logic here
  // Get user preferences
  const preferences: UserPreferences = await UserPreferencesService.getUserPreferences(userId);

  // Analyze user behavior
  const behaviorData: BehaviorData = await BehaviorAnalyzerService.analyzeUserBehavior(userId);

  // Generate recommendations based on preferences and behavior
  const recommendations: Recommendation[] = generateRecommendationsBasedOnData(preferences, behaviorData);

  return recommendations;
}

// Function to generate recommendations based on user data
function generateRecommendationsBasedOnData(preferences: UserPreferences, behaviorData: BehaviorData): Recommendation[] {
  // Implement the recommendation algorithm
}
// implement the other functions

export { main };

```

In this example:

- The **`main`** function is the primary function for generating product recommendations for a user.
- It calls two internal services (**`UserPreferencesService`** and **`BehaviorAnalyzerService`**) to collect user preferences and behavior data.
- The core recommendation logic is encapsulated in the **`generateRecommendationsBasedOnData`** function.

This structure adheres to the Hybrid Approach, allowing you to organize a project with complex business logic and multiple dependencies. Each feature operates autonomously, and the core logic for generating recommendations is organized in a structured and maintainable manner.

If **`UserPreferencesService`** is used by another feature outside the "recommendation" folder, it may be a good idea to create a separate "preferences" feature folder to accommodate it. This approach follows the principles of modularity and encapsulation.

**Revised Project Structure:**

```
plaintextCopy code
project-root/
|-- src/
|   |-- recommendation/
|   |   |-- recommendation.controller.ts
|   |   |-- internal/
|   |   |   |-- recommendation.model.ts
|   |   |   |-- recommendation.types.ts
|   |   |   |-- recommendationEngine.service.ts
|   |-- preferences/
|   |   |-- preferences.controller.ts
|   |   |-- internal/
|   |   |   |-- userPreferences.service.ts
|   |   |   |-- behaviorAnalyzer.service.ts
|-- app.ts
|-- package.json
|-- tsconfig.json
|-- README.md

```

With this structure:

- The "preferences" feature folder contains the services related to user preferences (**`userPreferences.service.ts`**) and behavior analysis (**`behaviorAnalyzer.service.ts`**).
- The "recommendation" feature folder remains focused on the recommendation logic.

This separation ensures that features are independent and maintain their own business logic. It also allows other parts of the application to access the "preferences" feature without the need to access the "recommendation" feature. The Hybrid Approach is all about organizing the code in a way that maximizes modularity and maintainability, and this adjustment aligns with those principles.

# Final verdict : 
 Here's why the Hybrid Approach is particularly advantageous in such scenarios:

### Modularity and Component Isolation:
 The Hybrid Approach's modularity allows you to compartmentalize different components into feature-specific modules. Each module can handle a distinct set of responsibilities, making it easier to manage and maintain various aspects of your project.
### Customization: 
With a mix-and-match approach to architectural patterns, you can customize each feature to fit its specific needs. For example, you can apply microservices architecture to the APIs logic while using a different approach for pub/sub or workflow components.
### Clear Separation of Concerns:
The Hybrid Approach enforces a clear separation of concerns, ensuring that each component's logic remains encapsulated. This separation makes it easier to understand, update, and debug individual features.
### Independence:
Components like APIs, pub/sub logic, and workflows often have different requirements and lifecycles. The Hybrid Approach allows you to develop, scale, and maintain these components independently.
### Scalability:
When your project comprises multiple components with varying scalability needs, the Hybrid Approach provides the flexibility to scale each feature or component separately, optimizing resource utilization.
### Complexity Management:
Complex projects with diverse components benefit from the Hybrid Approach's organization, as it prevents a monolithic codebase from becoming unwieldy.
### Interoperability:
The approach can be adapted for interoperability, allowing different components to communicate effectively.
### Maintainability:
The Hybrid Approach promotes maintainability, reducing the chances of codebase sprawl and making it easier to ensure that each component's logic is up to date and well-documented.

In summary, the Hybrid Approach is a versatile solution when you're dealing with projects that encompass a range of components, each requiring unique architectural considerations. Its flexibility, customization, and clear organizational structure make it well-suited for tackling the complexities of such projects.