title: Angular 11 print component inside another component
body: <p>I have a simple component where I've placed multiple buttons and I want to show those buttons in another component (functionality of buttons also comes from my buttons component) but i get this error in terminal</p>
  <pre><code>ERROR NullInjectorError: R3InjectorError(HelpdeskModule)[ButtonsComponent -&gt; ButtonsComponent -&gt; ButtonsComponent -&gt; ButtonsComponent]: 
    NullInjectorError: No provider for ButtonsComponent!
  </code></pre>
  <h1>Code</h1>
  <p><code>buttons.component.html</code></p>
  <pre><code>&lt;div class=&quot;mb-3&quot;&gt;
    &lt;nz-button-group&gt;
        &lt;button nz-button nzType=&quot;primary&quot; (click)=&quot;buttonClick('create button')&quot; class=&quot;ant-btn ant-btn-primary ant-btn-lg&quot;&gt;&lt;i nz-icon nzType=&quot;download&quot;&gt;&lt;/i&gt;Create New&lt;/button&gt;
    &lt;/nz-button-group&gt;
  &lt;/div&gt;
  </code></pre>
  <p><code>list.component.ts</code> (this is where i want to show those components)</p>
  <pre><code>  import { ButtonsComponent } from 'src/app/components/app/layout/buttons/buttons.component';
  
    constructor(
      private buttons: ButtonsComponent,
    ) { }
  </code></pre>
  <p>And <code>list.component.html</code></p>
  <pre><code>// I am uncertain about this part to be correct at all!
  {{buttons}}
  </code></pre>
  <p><strong>Any idea?</strong></p>
  <h1>Update</h1>
  <p>I've added <code>Injectable</code> to my buttons component like this: (just playing around to get them printed )</p>
  <pre><code>import { Component, OnInit, Injectable } from '@angular/core';
  import { NzNotificationService } from 'ng-zorro-antd'
  
  
  @Component({
    selector: 'app-buttons',
    templateUrl: './buttons.component.html',
    styleUrls: ['./buttons.component.scss']
  })
  
  @Injectable({
    providedIn: 'root'
  })
  
  export class ButtonsComponent implements OnInit {
    //
  }
  </code></pre>
  <p>and now I'm getting this error</p>
  <pre><code>ERROR TypeError: Invalid attempt to spread non-iterable instance.
  In order to be iterable, non-array objects must have a [Symbol.iterator]() method.
  </code></pre>