Converting an array object to a string within a TypeScript constructor: Step-by-step guide

After beginning my journey into learning Angular 2 with a basic understanding of typescript, I encountered an issue while trying to construct code using the constructor. The VS Code editor displayed a type error and I was unable to obtain the expected output in the browser. Below is the code I am working with, along with screenshots for reference. I would greatly appreciate any guidance on how to convert the Object within the Array to a string in the typescript constructor.

Shown below is the code snippet:

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

import { Hero } from './hero';

@Component({
selector: 'app-root',
templateUrl: './app.component.html',
styleUrls: ['./app.component.css']
})
export class AppComponent {
title: string;
heroes: Array<Hero>;
myHero: string;

constructor() {
this.title = "Tour Of Heroes";
this.heroes = [
new Hero(1, 'Windstorm'),
new Hero(13, 'Bombasto'),
new Hero(15, 'Magneta'),
new Hero(20, 'Tornado')
];
this.myHero = this.heroes[0];
}
}

Screenshots: VS Code Browser


Here is the code provided by the author (copied from comment):

<h1>{{title}}</h1>
<h2>My favorite hero is: {{myHero}}</h2>
<p>Heroes:</p>
<ul>
  <li *ngFor="let hero of heroes"> {{ hero }} </li>
</ul>

Answer №1

this.topHero = this.heroes[0].name; // display the top hero's name

If you prefer to maintain your selected hero as an object, then showcase the name in the template.

app.component.html

{{topHero.name}}

When it comes to the array, you must iterate through it and highlight something intriguing about each object within the array.

<div *ngFor="#hero of heroes">
  {{hero.name}}
</div>

Based on your feedback, here is the updated code that showcases the name of the topHero instance and iterates over the heroes array.

<h1>{{title}}</h1>
<h2>My ultimate hero is: {{topHero.name}}</h2>
<p>Heroes:</p>
<ul> <li *ngFor="let hero of heroes"> {{ hero.name }} </li> </ul>

Answer №2

When assigning an object of the Hero class to a string variable, it causes compatibility issues. Instead of changing the variable to a string, declare it with the type of Hero class. So,

myHero: string;

should be updated to

myHero: Hero;

Then, in the template, you can use it with properties like this:

<h1>{{title}}</h1>
   <h2>My favorite hero is: {{myHero.name}}</h2>
      <p>Heroes:</p>
         <ul>
             <li *ngFor="let hero of heroes"> {{ hero.name}} </li>
        </ul>

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