Angular Forms: Reactive vs Template-Driven #2

Understanding Reactive vs Template-Driven Forms is very important in Angular interviews, especially for form-heavy apps like admin dashboards or CRMs.

Let’s break this down in pen-and-paper-friendly style so you can write notes easily and revise quickly.

Angular offers two approaches to build forms:

🧩 1. Template-Driven Forms

• Easy to write
• Uses Angular directives (ngModel, required, etc.)
• Best for simple forms

✅ Key Features:

• 2-way binding with [(ngModel)]
• Uses FormsModule
• Validations done via HTML attributes

🔍 Example:

HTML (template-driven):

<form #formRef="ngForm" (ngSubmit)="submitForm(formRef)">
  <input type="text" name="username" [(ngModel)]="user.name" required />
  <button type="submit">Submit</button>
</form>

TS:

user = { name: '' };

submitForm(form: NgForm) {
  console.log(form.value); // Access all form data
}

🧠 2. Reactive Forms

• More powerful & scalable
• Form is created and managed in TypeScript
• Best for complex, dynamic forms

✅ Key Features:

• Uses FormControl, FormGroup, FormBuilder
• Needs ReactiveFormsModule
• All logic lives in component

🔍 Example:

TS:

form: FormGroup;

ngOnInit() {
  this.form = this.fb.group({
    username: ['', Validators.required]
  });
}

submitForm() {
  console.log(this.form.value);
}

HTML:

<form [formGroup]="form" (ngSubmit)="submitForm()">
  <input type="text" formControlName="username" />
  <button type="submit">Submit</button>
</form>

⚔️ Comparison Table

💡 Interview Tips

• Use template-driven for simple contact/login forms
• Use reactive for forms with:
  • Dynamic fields (like Add/Remove rows)
  • Conditional validations
  • Complex interactions

🎯 Common Interview Questions

1. Which form type is better for dynamic validations?
   👉 Reactive Forms
2. What’s the difference between FormControl & ngModel?
   👉 FormControl is for reactive forms (TS driven), ngModel is for template-driven (HTML driven)
3. Can we mix both?
   👉 Technically yes, but Angular recommends not to mix.

Would you like to go deeper into:

• FormArray in Reactive Forms (used in tables or dynamic inputs)?
• Or learn built-in validation + custom validators next?

Just say the word — I’ll prep it in your note-friendly format! 📖🖊️