Heterogeneous enums in Typescript - Mini Project: Build & Apply

Heterogeneous enums

📖 Scenario: You are creating a simple program to represent different types of user roles in a system. Some roles are identified by numbers, and others by strings. This mix is called a heterogeneous enum.

🎯 Goal: Build a TypeScript heterogeneous enum called UserRole with both numeric and string values, then print one of the roles.

📋 What You'll Learn

Create a heterogeneous enum called UserRole

Include numeric and string values in the enum

Print the value of UserRole.Admin

💡 Why This Matters

🌍 Real World

Heterogeneous enums are useful when you need to represent a set of related constants that have different types, like numeric IDs and string codes, in a clear and organized way.

💼 Career

Understanding enums helps in writing clean, maintainable code in TypeScript, which is widely used in web development and many software projects.

1

Create the heterogeneous enum

Create a heterogeneous enum called UserRole with these exact entries: Admin = 1, Editor = 'EDITOR', Viewer = 3, Guest = 'GUEST'.

Typescript

// Your code here

Need a hint?

Use the enum keyword and assign numbers or strings to each member.

2

Add a variable to hold a role

Create a variable called currentRole and set it to UserRole.Admin.

Typescript

enum UserRole {
    Admin = 1,
    Editor = 'EDITOR',
    Viewer = 3,
    Guest = 'GUEST'
}

// Your code here

Need a hint?

Use let currentRole = UserRole.Admin; to assign the enum value.

3

Write a function to describe the role

Create a function called describeRole that takes a parameter role of type UserRole and returns a string. Inside, use a switch statement on role with cases for UserRole.Admin, UserRole.Editor, UserRole.Viewer, and UserRole.Guest. Return these exact strings respectively: 'Administrator', 'Content Editor', 'Content Viewer', 'Guest User'. Include a default case returning 'Unknown Role'. Assign the result of describeRole(currentRole) to a variable called roleDescription.

Typescript

enum UserRole {
    Admin = 1,
    Editor = 'EDITOR',
    Viewer = 3,
    Guest = 'GUEST'
}

let currentRole = UserRole.Admin;

// Your code here

Need a hint?

Use a switch statement to return the correct string for each role.

4

Print the role description

Write a console.log statement to print the value of roleDescription.

Typescript

enum UserRole {
    Admin = 1,
    Editor = 'EDITOR',
    Viewer = 3,
    Guest = 'GUEST'
}

let currentRole = UserRole.Admin;

function describeRole(role: UserRole): string {
    switch (role) {
        case UserRole.Admin:
            return 'Administrator';
        case UserRole.Editor:
            return 'Content Editor';
        case UserRole.Viewer:
            return 'Content Viewer';
        case UserRole.Guest:
            return 'Guest User';
        default:
            return 'Unknown Role';
    }
}

let roleDescription = describeRole(currentRole);

// Your code here

Need a hint?

Use console.log(roleDescription); to print the role description.