Services & DI — Angular Technical Interview Questions & Answers

Services & DI

Services & DI

  • Services & DI (and) is a Angular topic. In plain words you use it for MarksService shared by two pages in the campus app. Don’t start with a slogan — start with that picture.
  • Smallest example: @Injectable + constructor inject. Type it, run it, and say what you see. If you can do that from memory, you know Services & DI (and).
  • From the example next to this theory: Services & DI: toggle open.
  • Trap: new MarksService() in each component. Fix that before you talk about advanced Angular.
  • Viva: what is Services & DI (and)? Then show @Injectable + constructor inject. Then name the trap.

Technical Interview Tip: What is Services & DI (and)? Show this: @Injectable + constructor inject. Trap: new MarksService() in each component.

Code Examples for Services & DI

Services & DI — 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;
  }
}

Services & DI: toggle open. Say whether the panel is on screen after one click.

How to Explain Services & DI to an Interviewer

What is Services & DI (and)?

Used for MarksService shared by two pages the campus app Not just the heading

Give one small example of Services & DI (and).

@Injectable + constructor inject Services & DI: toggle open

What mistake do beginners make with Services & DI (and)?

new MarksService() in each component Show the fix

Where do you use Services & DI (and)?

the campus app MarksService shared by two pages