Introduction

In Angular applications, one common challenge is handling data from external APIs that doesn’t match your internal data format. The Adapter Pattern is a latest design pattern that helps you deal with this problem by transforming the incoming data into the desired format. In this post, we’ll see how to implement the Adapter Pattern in Angular in two different ways:

• With NGRx: When you want to manage state in a more centralized, reactive manner.
• Without NGRx: When you want a simpler solution using just Angular services and components.

What is the Adapter Pattern?

A structural design pattern called the Adapter Pattern makes it possible for incompatible interfaces to work together. It serves as a bridge, transforming data formats so your application can process them more readily. This is especially helpful when interacting with libraries, legacy systems, or third-party APIs that return data in an unexpected format. Here is the following key points as:

• Purpose: The goal is to decouple the internal application logic from external data formats, making the system more flexible and maintainable.
• Real-World Analogy: Think of a travel adapter for electronics. You plug your device (e.g., a phone) into an adapter that adjusts the power and plug format to be compatible with different sockets in various countries. In the same way, the Adapter Pattern “adjusts” data to be compatible with your app’s requirements.

Scenario: Incompatible Data Format from an External API

Imagine you’re building an e-commerce application, and you need to fetch product information from an external API. The API provides product data in a format like this:

productId, productName, productPrice, etc. However, your application needs data in a different format to match the UI requirements:
id, name, price (formatted as a string with a dollar sign), description, stock, etc.

Here, the Adapter Pattern would be used to adapt the data from the API’s format into the format that your Angular app needs.

Using the Adapter Pattern Without NGRx:

We can implement the Adapter Pattern using Angular services and components. Focus on the following:

Service and Component Structure: In Angular, services can be used to handle data fetching and transformation.
Components can call the service to fetch the transformed data and then bind it to the UI.

Process Flow:

• Fetch data from an external API.
• Use an adapter function or class to transform the API data into the required internal format.
• Store the transformed data in the component’s state (e.g., as a class property).
• Bind the transformed data to the template for display.

Benefits of Using This Approach:

• Simplicity: This method is easy to implement and doesn’t require complex state management solutions.
• Direct Control: Since data is handled within components and services, developers have full control over the data-fetching and transformation process.

When to Use This Approach:

• Smaller applications or projects where state management is not needed.
• Projects where centralized state management is unnecessary or adds unnecessary complexity.

Using the Adapter Pattern With NGRx:

The Adapter Pattern can be applied with NGRx, focusing on the following aspects:

NGRx Overview:

• NGRx is a state management library for Angular that follows the Redux pattern.
• It centralizes the application’s state, providing a global store that all components can access.
• NGRx also uses concepts like actions, reducers, effects, and selectors to manage state changes.

Process Flow:

• Similar to the approach without NGRx, you fetch the data from an API.
• However, in an NGRx-based application, the transformed data (using an adapter) is dispatched to the global store through actions
• Reducers update the state based on the dispatched actions.
• Components subscribe to the store using selectors to access the adapted data and render it in the UI.

Benefits of Using NGRx with the Adapter Pattern:

• Scalability: NGRx is ideal for larger applications with more complex state management needs. It centralizes the state, which is useful when you have multiple components that need access to the same data.
• Predictable State: Since NGRx follows a unidirectional data flow, the state is predictable, and side effects are managed in effects, making it easier to debug and maintain.
• Reactivity: NGRx leverages Observables, which make the data flow highly reactive. This means that when the data in the store changes, the components automatically update.

When to Use This Approach:

For larger Angular applications that require a global state or need to share state between multiple components.
When you have complex state management logic (e.g., handling side effects or asynchronous data fetching) that benefits from a more structured approach.

When to Choose One Over the Other:

To help you decide which approach is best for your scenario, here’s a comparison of the two methods: with NGRx and without NGRx:

Without NGRx:

• Best for smaller applications
• Simple and minimal setup
• Localized state management within components/services
• Manual reactivity handling

With NGRx:

• Best for larger applications with complex state
• Centralized, global state management
• Reactive data flow with automatic updates
• Scalable and maintainable in the long run

Conclusion:

The Adapter Pattern in Angular provides a clean way to manage and transform data from external sources into a format your application can easily consume. Whether you choose to implement it with or without NGRx depends on your application’s complexity and state management needs. Both approaches have their advantages, and understanding the trade-offs will help you decide which is right for your project.