Search⌘ K
AI Features
Home
Courses
Learning Angular

Interfaces in TypeScript

Explore how to define and use TypeScript interfaces to maintain consistent type structures in Angular applications. Understand creating contracts for classes and functions, incorporating optional members, and leveraging interfaces for mocking and testing. Gain practical skills to improve code reliability and testability in scalable Angular projects.

We'll cover the following...

As applications scale and more classes are created, we need to find ways to ensure consistency and rule compliance in our code. One of the best ways to address the consistency and validation of types is to create interfaces. An interface is a code contract that defines a particular schema. Any artifacts such as classes and functions that implement an interface should comply with this schema. Interfaces are beneficial when we want to enforce strict typing on classes generated by factories or when we define function signatures to ensure that a particular typed property is found in the payload.

In the following snippet, we define the Vehicle interface:

TypeScript 4.9.5
interface Vehicle {
    make: string; 
}

Any class that implements the preceding interface must contain a member named make, which must be typed as a string:

TypeScript 4.9.5
class Car implements Vehicle {
    make: string; 
}

Interfaces are also beneficial for defining the minimum set of members any artifact must fulfill, becoming an invaluable method to ensure consistency throughout our code base. ...