What are enums and how do you use them in TypeScript?

Q: What are enums and how do you use them in TypeScript?

Learn the answer to "What are enums and how do you use them in TypeScript?" with detailed explanations, code examples, and best practices on DeployU.

The Scenario

You are a frontend engineer at a social media company. You are writing a new feature that needs to represent a set of related constants, such as the different roles that a user can have.

You could use a set of const variables, but this would not be a very elegant solution.

The Challenge

Explain what enums are in TypeScript and how you would use them to solve this problem. What are the key benefits of using enums?

Wrong Approach

A junior engineer might not be aware of enums. They might try to solve this problem by using a set of `const` variables, which would be a less elegant and less type-safe solution.

Addresses symptoms, not root cause

Right Approach

A senior engineer would know that enums are the perfect tool for this job. They would be able to explain what enums are and how to use them to create a set of named constants.

Step 1: Understand What Enums Are

An enum is a way to define a set of named constants.

Step 2: The Different Types of Enums

Type	Description
Numeric	The default type of enum. The first member is initialized to 0, and each subsequent member is incremented by 1.
String	Each member must be initialized with a string value.
Heterogeneous	A mix of numeric and string members.

Step 3: Use an Enum

Here’s how we can use an enum to represent the different roles that a user can have:

enum Role {
  Admin,
  Editor,
  Viewer
}

const myRole: Role = Role.Admin;

The Benefits of Using Enums

Benefit	Description
Readability	Enums make your code more readable by giving names to a set of related constants.
Type Safety	Enums provide compile-time type safety, which can help you to catch errors early.

Systematic, production-ready debugging

Practice Question

You have a numeric enum and you want to get the name of a member from its value. How would you do this?

Questions