Interfaces vs Types in TypeScript: Understanding the Differences
Tags: webdev, javascript, beginners, programming
Published: 2023-08-23 15:18:10

In TypeScript, creating custom data structures involves two key players: interfaces and types. These tools, although similar, have specific roles and benefits. This article delves into the practical aspects of interfaces and types, exploring their features and suggesting optimal situations for their application. Let's uncover the nuanced world of TypeScript's essential building blocks.

## Interfaces
Interfaces are primarily used to define the shape of objects or classes. They act as contracts that specify which properties an object must have and their respective types. Interfaces are ideal for maintaining consistent structures across various parts of your codebase.


![Image description](https://dev-to-uploads.s3.amazonaws.com/uploads/articles/92gaoz1wyxtsr6v5eedv.png)

In this scenario, the Furniture interface ensures that any object assigned to the chair variable adheres to the required properties and types.

## Types
Types offer a more versatile approach to defining custom types. While they can define object shapes just like interfaces, their true power lies in handling unions, intersections, tuples, and complex type compositions. 



![Image description](https://dev-to-uploads.s3.amazonaws.com/uploads/articles/11pmjime6ncgs8s8zyij.png)

The example code above creates custom types for managing furniture-related data.It defines FurnitureID for IDs that can be either strings or numbers. FurniturePiece describes furniture properties like color, newness, and width. FurnitureWithDimensions extends FurniturePiece to include height and depth. FurnitureOwner includes ID and name for furniture owners, while FurnitureShop contains details about the shop manager and staff.

## Making the Choice Between Interfaces and Types

**- Interfaces**
Choose interfaces when you want to lay out how objects should be built and make sure everyone follows the same rules. This helps keep your code neat and easy to understand, making it simpler to manage and work together on. Interfaces give your code a solid base, making it easier for different parts to work well together.

**- Types**
Go for types when things get more complicated, like dealing with combinations, overlaps, special rules, or conditions. Types are your go-to for handling intricate situations, giving you more freedom in defining how things should behave. For instance, you can use types to describe different kinds of data in a detailed and adaptable way

Although interfaces and types serve different purposes, they can sometimes be used interchangeably. Your decision between them should be based on your project's needs and your coding preferences. If you want well-defined object layouts, go for interfaces. For complex type handling, types are your choice.

## Conclusion
Interfaces and types are essential tools in TypeScript to ensure your code has the right types. Knowing their differences helps you choose wisely. Whether you're creating basic shapes or handling complex types, TypeScript's interfaces and types offer the flexibility and structure for strong and manageable code.