Recap - Handling Null Safely

Part of the Fundamentals section of Coddy's Dart journey — lesson 82 of 94.

Challenge

Easy

You're building a user profile system for a mobile app. Create a UserProfile class that demonstrates your understanding of Dart's null safety features.

Implement a class UserProfile with the following:

Non-nullable properties (must always have a value):
- id of type int
- createdDate of type String
Nullable properties (can be null at initialization):
- name of type String?
- email of type String?
- age of type int?
Late-initialized property:
- displayName of type String, declared using the late keyword
Constructor:
- Accepts id and createdDate as required parameters
- Initializes displayName to "Guest"

Method: void printProfile() Prints the user profile with the following format:

User Profile:
ID: <id>
Created: <createdDate>
Name: <name or 'Not provided'>
Email: <email or 'Not provided'>
Age: <age or 'Not provided'>
Display Name: <displayName>
-------------------

Method: void updateEmail(String? newEmail)
- Updates the email property with the new value.
Method: String getDisplayName()
- If name is not null, sets displayName = name! (using null assertion operator)
- Returns the current value of displayName

Important: After updating the name property, you must call getDisplayName() to update the displayName field before printing the profile again.

Complete the code to create a profile, update it, and display the information as shown in the expected output.

Try it yourself

void main() {
  // Create a user profile
  final profile = UserProfile(1, 'today');
  
  // Print initial profile
  profile.printProfile();
  
  // Update profile
  profile.name = 'John Doe';
  profile.updateEmail('john@example.com');
  profile.age = 30;
  
  // Update display name and print updated profile
  profile.getDisplayName(); // Call this to update displayName
  profile.printProfile();
}

class UserProfile {
  // TODO: Add properties (id, createdDate, name, email, age, displayName)
  
  // TODO: Create constructor
  
  // TODO: Implement printProfile() method
  
  // TODO: Implement updateEmail() method
  
  // TODO: Implement getDisplayName() method
}