What are Angular Forms
💡 Concept Name
Angular Forms – A set of tools and APIs provided by Angular to build and manage forms with validation, input tracking, and data-binding.
📘 Quick Intro
Angular supports two types of forms: Template-driven (declarative and easy to use) and Reactive forms (programmatic and scalable). Both approaches allow binding user input to form data and applying validations.
🧠 Analogy / Short Story
Imagine a paper form: You can either fill it directly (template-driven) or have software autofill and validate each section (reactive). Angular gives you both options to manage forms in web apps.
🔧 Technical Explanation
- 📄 Template-driven forms use Angular directives like
ngModel. - 🧠 Reactive forms use
FormControl,FormGroup, andFormBuilder. - 🔍 Support for built-in and custom validators.
- 🔄 Real-time validation and status tracking.
- 📦 FormsModule and ReactiveFormsModule are required to use forms.
🎯 Purpose & Use Case
- ✅ Capturing user input (login, signup, contact forms).
- ✅ Validating and processing data before submitting.
- ✅ Displaying validation messages and input feedback.
- ✅ Dynamically building forms based on data models.
💻 Real Code Example
// Reactive Form Example
import { FormGroup, FormControl, Validators } from '@angular/forms';
loginForm = new FormGroup({
email: new FormControl('', [Validators.required, Validators.email]),
password: new FormControl('', Validators.required)
});
onSubmit() {
console.log(this.loginForm.value);
}
❓ Interview Q&A
Q1: What are the two types of forms in Angular?
A: Template-driven and Reactive forms.
Q2: What module is required for template-driven forms?
A: FormsModule.
Q3: What are FormGroup and FormControl?
A: Classes used in reactive forms to group and manage controls.
Q4: How does Angular support form validation?
A: Through built-in and custom validators.
Q5: Which approach is preferred for large-scale applications?
A: Reactive forms for better control and scalability.
📝 MCQs
Q1. Which Angular module supports template-driven forms?
- ReactiveFormsModule
- FormsModule
- BrowserModule
- HttpClientModule
Q2. Which is used in reactive forms?
- ngModel
- FormGroup
- ngForm
- ngSubmit
Q3. Which form approach uses ngModel?
- Reactive
- Dynamic
- Template-driven
- Event-driven
Q4. What is FormControl used for?
- To style forms
- To submit forms
- To manage value and validation of a form field
- To create templates
Q5. What is required for reactive forms?
- FormsModule
- ReactiveFormsModule
- CommonModule
- NgModule
Q6. Which form approach is easier for beginners?
- Reactive
- Template-driven
- Dynamic
- Stateless
Q7. How does Angular track form validity?
- Using ngModel
- Using console logs
- Using form status properties
- Using decorators
Q8. What does a FormGroup contain?
- One FormControl
- Multiple FormControls
- A template
- A directive
Q9. Which directive is used for template-driven form validation?
- ngSubmit
- ngControl
- ngModel
- ngGroup
Q10. Which is a built-in Angular validator?
- Validators.length
- Validators.validate
- Validators.required
- Validators.set
💡 Bonus Insight
You can combine both approaches (reactive + template) in complex forms using the ControlValueAccessor interface to build reusable form components.
📄 PDF Download
Need a handy summary for your notes? Download this topic as a PDF!