Forms — Angular Technical Interview Questions & Answers

Forms

Forms

  • Template-driven: ngModel on the fields, FormsModule. Fast for a tiny name+roll form. Reactive: FormGroup / FormControl in TS, ReactiveFormsModule. Better when validators grow.
  • Board: name required, roll number. Invalid → Save disabled. Don’t trust the UI — validate again on the server. Trap: mixing ngModel and FormControl on the same input.

Technical Interview Tip: When ngModel vs FormGroup. One required validator.

Code Examples for Forms

Forms — working example

import { Component } from "@angular/core";

@Component({
  selector: "app-root",
  template: `
    <h1>{{ title }}</h1>
    <button (click)="toggle()">Toggle</button>
    <p *ngIf="open">Panel open</p>
  `,
})
export class AppComponent {
  title = "Angular practice";
  open = true;
  toggle() {
    this.open = !this.open;
  }
}

Forms: toggle open. Say whether the panel is on screen after one click.

How to Explain Forms to an Interviewer

Template-driven vs reactive forms?

ngModel vs FormControl Reactive scales better