TypeScript Interfaces

What is an Interface?

An interface defines the structure of an object.

It tells TypeScript what properties an object should have.

Why Use Interfaces

• Enforce structure
• Improve readability
• Reduce errors
• Reuse types

Optional Properties

Use ? to make properties optional.

Readonly Properties

Methods in Interfaces

Interfaces can include functions.

Extending Interfaces

You can extend one interface from another.

Interfaces with Functions

Full Example

Why Interfaces are Important

• Used in APIs
• Used in React props
• Structure large applications
• Improve maintainability

Common Mistakes

• Missing required properties
• Wrong property types
• Confusing interface and type

Practice

Create an interface for a car with brand, model, and a method that prints details.

Need Help?

Ask the AI if you need help understanding or want to dive deeper in any topic