title: How to inject service into class (not component)
body: <p>I'd like to inject a service into a class that is <strong>not a component</strong>.</p>
  <p>For example:</p>
  <p><em>Myservice</em></p>
  <pre><code>import {Injectable} from '@angular/core';
  @Injectable()
  export class myService {
    dosomething() {
      // implementation
    }
  }
  </code></pre>
  <p><em>MyClass</em></p>
  <pre><code>import { myService } from './myService'
  export class MyClass {
    constructor(private myservice:myService) {
  
    }
    test() {
       this.myservice.dosomething();
    }
  }
  </code></pre>
  <p>I tried and it doesn't work. It seems like service need to be used in only component or service.</p>
  <p>Is there a way to use a service in a normal class? or it's a bad practice to use a service in a normal class.</p>
  <p>Thank you.</p>