Angular and RxJS Online Test

Finish the ShoppingList component. The component will receive an array of strings as the items array. It should render one li element per item in the array.

For example, if the items array is ["Bread", "Eggs", "Milk"], the rendered HTML should look like:

<ul>
  <li>Bread</li>
  <li>Eggs</li>
  <li>Milk</li>
</ul>

The code for running the example case locally is provided here.

Consider the following RxJS code for testing how a given damage Subject affects the health of a Player object in a game:

class Player {
  name: string;
  health: number;
  damageSubscription: Subscription;

  constructor(name, damageSubject) {
    this.name = name;
    this.health = 100;
    this.damageSubscription = damageSubject.subscribe((damage) => {
      this.health -= damage;
      console.log(this.name + " was hurt for " + damage + " damage");
    });
  }

  takeCover() {
    this.damageSubscription.unsubscribe();
    interval(1000)
      .pipe(
        takeWhile(() => this.health < 100),
        map(() => 10),
        tap(() => console.log(this.name + " is healing, current health is " + this.health))
      )
      .subscribe((heal) => {
        this.health += heal;
      });
  }
}
const explosion = new Subject();
const john = new Player("John", explosion);
const sam = new Player("Sam", explosion);

explosion.next(10);
john.takeCover();
explosion.next(20);

const paul = new Player("Paul", explosion);
sam.takeCover();
explosion.next(20);
paul.takeCover();

What options will be true after the above code is run?

An image gallery is a set of images with corresponding remove buttons. This is the HTML code for a gallery with two images:

<div>
  <div class="image">
    <img src="https://bit.ly/3lmYVna">
    <button class="remove">X</button>
  </div>
  <div class="image">
    <img src="https://bit.ly/3flyaMj">
    <button class="remove">X</button>
  </div>
</div>

Implement the ImageGallery component that accepts a links input and renders the gallery described above so that the first item in the links input is the src attribute of the first image in the gallery. It should also implement the following logic: When the button is clicked, the image that is in the same div as the button should be removed from the gallery.

For example, after the first image has been removed from the gallery above, it's HTML code should look like this:

<div>
  <div class="image">
    <img src="https://bit.ly/3flyaMj">
    <button class="remove">X</button>
  </div>
</div>

The code for running the example case locally is provided here.

Finish the AddressListComponent's template so that it renders one li element per address and it correctly one-way binds each field of the AddressComponent field.

For example, if the addresses array is:

[{ street: "Third Avenue‎", city: "New York", zipCode: "10001" },
 { street: "Constitution Avenue", city: "Washington", zipCode: "20001" }]

the template should render to:

<ul>
  <li>
    <app-address>
      <p>Third Avenue</p>
      <p>New York</p>
      <p>10001</p>
    </app-address>
  </li>
  <li>
    <app-address>
      <p>Constitution Avenue</p>
      <p>Washington</p>
      <p>20001</p>
    </app-address>
  </li>
</ul>

The code for running the example case locally is provided here. 

Consider the following application module:

import { NgModule }             from '@angular/core';
import { RouterModule, Routes } from '@angular/router';
import { HomeComponent }        from './home.component';
import { ItemDetailComponent }  from './item-detail.component';
const routes: Routes = [
    { path: '', redirectTo: '/home', pathMatch: 'full' },
    { path: 'home',  component: HomeComponent },
    { path: 'detail/:id', component: ItemDetailComponent, outlet: 'route1' }
];
@NgModule({
    imports: [ RouterModule.forRoot(routes) ],
    exports: [ RouterModule ]
})
export class AppRoutingModule {}

Which of the following statements about the routers behavior are correct?

Consider the following component, which can be used to model an animal and the noise it makes.

import {Component, Input, Output} from '@angular/core';

@Component({
  selector: 'animal-noise',
  template: `
    <span>{{animal}}</span>
    <button (click)="makeNoise()">Make noise</button>
  `
})
export class AnimalNoise {
  @Input('animal') animal: string;
  @Input('noise') noise: string;

  makeNoise() {
    alert(`${this.noise}`);
  }
}

Select the statements about the AnimalNoise component that are correct.

Consider the following RxJS code for pushing and logging weather data:

const weatherSubject = new _______________({temperature: 0 , rainChance: 0});
const sendWeatherData = (weatherData) => {
  weatherSubject.____(weatherData);
};

sendWeatherData({temperature: 35.5 , rainChance: 20});
sendWeatherData({temperature: 34 , rainChance: 25});

weatherSubject.subscribe((x) => {
  console.log("Current Temperature: " +  x.temperature);
});

sendWeatherData({temperature: 28 , rainChance: 50});

weatherSubject.subscribe((x) => {
  console.log("Chance of rain: " + x.rainChance);
});

sendWeatherData({temperature: 25 , rainChance: 90});

Fill in the blanks above so that the following output is produced after running it:

Current Temperature: 34
Current Temperature: 28
Chance of rain: 50
Current Temperature: 25
Chance of rain: 90

An online streaming platform uses the following RxJS code to log the number of seconds passed in a video:

const seconds = interval(1000).pipe(
  map((x) => x + 1),
  startWith(0)
);

const logger = seconds.subscribe((x) =>
  console.log(`Seconds passed: ${x}`)
);

setTimeout(() => {
  logger.unsubscribe();
}, 5000);

What options will be true about seconds and logger after the code above is executed?

Consider the following component:

import { Component, Input } from '@angular/core';

@Component({
  selector: 'welcome',
  template: `<h1>Welcome to {{name}}!</h1>`,
  styles: [`h1 { font-family: Lato; }`]
})
export class WelcomeComponent  {
  @Input() name: string;
}

Select the statements about its use (in another components template or module) that are correct.

Which of the following statements about components in Angular are correct?