Required type in Typescript - Mini Project: Build & Apply

Using the Required Type in TypeScript

📖 Scenario: Imagine you are building a simple user profile system where some user information is optional at first but later you want to make sure certain fields are definitely filled in.

🎯 Goal: You will create a user object with optional fields, then use TypeScript's Required type to make all fields mandatory, and finally print the updated user object.

📋 What You'll Learn

Create an interface User with optional properties name, email, and age

Create a variable user of type User with only name set

Create a new type CompleteUser using Required<User>

Create a variable completeUser of type CompleteUser with all properties set

Print the completeUser object

💡 Why This Matters

🌍 Real World

In real projects, you often start with optional data and later require all fields to be filled before saving or processing.

💼 Career

Understanding TypeScript utility types like <code>Required</code> helps you write safer and clearer code, a valuable skill for frontend and backend developers.

1

Create the User interface and user variable

Create an interface called User with optional properties name (string), email (string), and age (number). Then create a variable called user of type User with only name set to "Alice".

Typescript

// Your code here

Need a hint?

Use ? after property names to make them optional in the interface.

2

Create the CompleteUser type using Required

Create a new type called CompleteUser using Required<User> to make all properties required.

Typescript

interface User {
  name?: string;
  email?: string;
  age?: number;
}

const user: User = {
  name: "Alice"
};

// Your code here

Need a hint?

Use type CompleteUser = Required<User>; to make all properties required.

3

Create a completeUser variable with all properties

Create a variable called completeUser of type CompleteUser and set all properties: name to "Alice", email to "[e-mail]", and age to 30.

Typescript

interface User {
  name?: string;
  email?: string;
  age?: number;
}

const user: User = {
  name: "Alice"
};

type CompleteUser = Required;

// Your code here

Need a hint?

All properties must be present because CompleteUser requires them.

4

Print the completeUser object

Write a console.log statement to print the completeUser object.

Typescript

interface User {
  name?: string;
  email?: string;
  age?: number;
}

const user: User = {
  name: "Alice"
};

type CompleteUser = Required;

const completeUser: CompleteUser = {
  name: "Alice",
  email: "[e-mail]",
  age: 30
};

// Your code here

Need a hint?

Use console.log(completeUser); to print the object.