title: How can I get new instances of a class using Injector instead of singleton
body: <p>I have two injectable classes in my angular application </p>
  
  <pre><code>@Injectable()
  class B {}
  
  @Injectable()
  class A {
    constructor(b:B) { }
  }
  </code></pre>
  
  <p>I want class A to be Singleton and class B to be Transient </p>
  
  <p>I came to know I can use <strong>ReflectiveInjector.resolveAndCreate</strong> in class A to get an instance of class B. Any better way of achieving this ? </p>