Building a Dynamic User Registration Form with Angular Reactive Forms

This challenge focuses on building a robust and dynamic user registration form using Angular's Reactive Forms module. You will learn how to manage form state, validate user input, and handle form submissions effectively in a real-world application scenario. This is a fundamental skill for building interactive and user-friendly web applications.

Problem Description

Your task is to create an Angular component that implements a user registration form. This form should collect essential user information and provide real-time validation feedback.

Key Requirements:

1. Form Structure: The form should include the following fields:

   • Full Name: A text input.
   • Email: An email input, requiring a valid email format.
   • Password: A password input, with a minimum length requirement.
   • Confirm Password: A password input, which must match the Password field.
   • Terms and Conditions: A checkbox that must be checked for submission.

2. Reactive Forms Implementation: Use Angular's ReactiveFormsModule to build the form. This involves:

   • Creating a FormGroup to encapsulate all form controls.
   • Creating FormControl instances for each form field.
   • Using FormBuilder for efficient form group creation.

3. Validation: Implement the following validations:

   • Required Fields: All fields (except Terms and Conditions, which is handled by a separate validator) should be required.
   • Email Format: The Email field must be a valid email address.
   • Password Strength: The Password field must have a minimum length of 8 characters.
   • Password Match: The Confirm Password field must exactly match the Password field.
   • Terms Acceptance: The Terms and Conditions checkbox must be checked.

4. Error Display: Provide clear and user-friendly error messages to the user for each validation rule that is broken. Error messages should appear next to the respective input fields and be dynamically updated as the user types or interacts with the form.

5. Submission Handling:

   • The "Register" button should be disabled if the form is invalid or has not been touched.
   • Upon successful submission (when the form is valid), log the form's value to the console and display a success message to the user (e.g., using an alert or a temporary message within the component).
   • The form should be reset after a successful submission.

Expected Behavior:

• As a user types, validation errors should appear immediately or upon losing focus, guiding them to correct input.
• The "Register" button should be enabled only when all validation rules are met.
• If the user tries to submit an invalid form, the errors should be clearly visible.
• Upon successful registration, the form data should be accessible for further processing (simulated by console logging), and the form should be cleared.

Edge Cases to Consider:

• User attempts to submit without filling out any fields.
• User enters invalid data and then corrects it – ensure error messages disappear correctly.
• User enters a password, then changes it – ensure "Confirm Password" validation updates accordingly.

Examples

Example 1: Initial State

• Input: The component is loaded, and no user interaction has occurred.
• Output: All input fields are empty. The "Register" button is disabled. No error messages are displayed.
• Explanation: The form is in its default, untouched state, and therefore considered invalid.

Example 2: User Enters Valid Data and Submits

• Input:
  • Full Name: "John Doe"
  • Email: "john.doe@example.com"
  • Password: "SecurePassword123"
  • Confirm Password: "SecurePassword123"
  • Terms and Conditions: Checked
• Output:
  • The "Register" button becomes enabled.
  • Upon clicking "Register," the form data {"fullName": "John Doe", "email": "john.doe@example.com", "password": "SecurePassword123", "confirmPassword": "SecurePassword123", "termsAccepted": true} is logged to the console.
  • An alert or message "Registration Successful!" is displayed.
  • The form fields are reset to their initial empty state.
• Explanation: All validation rules are satisfied, allowing for successful submission.

Example 3: User Enters Invalid Data

• Input:
  • Full Name: "" (empty)
  • Email: "invalid-email"
  • Password: "short"
  • Confirm Password: "mismatch"
  • Terms and Conditions: Unchecked
• Output:
  • Error messages displayed for:
    • "Full Name is required."
    • "Invalid email format."
    • "Password must be at least 8 characters long."
    • "Passwords do not match."
    • "You must accept the terms and conditions."
  • The "Register" button remains disabled.
• Explanation: Multiple validation rules are broken, preventing form submission and providing feedback.

Constraints

• Angular version: Latest stable release (e.g., Angular 17+).
• Use TypeScript for all component and service logic.
• The solution should be contained within a single Angular component.
• No external libraries for form management are allowed, only Angular's built-in ReactiveFormsModule.
• The "Register" button must be a <button type="submit"> within the form element.

Notes

• Consider using Angular's built-in validators like Validators.required, Validators.email, and Validators.minLength.
• For the password match validation, you'll need to create a custom validator function.
• Think about how to conditionally display error messages based on the form control's state (e.g., touched, dirty, invalid).
• The terms and conditions validator will likely involve checking a checkbox control.
• You can simulate the API call for registration by simply logging the form data to the console.