title: does angular have the "computed property" feature like in vue.js?
body: <p>I learnt Vue.js first, and now have a project in Angular 4 so I just learnt Angular. I find everything is not that different from Vue except the "Computed Property". In Vue, I can create a computed property that listens to changes of other properties and run calculations automatically. </p>
  
  <p>For example(in Vue 2): </p>
  
  <pre><code>computed: {
      name(){
          return this.firstname + ' ' + this.lastname;
      }
  }
  </code></pre>
  
  <p>The name property will only recalculate when one of firstname or lastname change. How to handle this in Angular 2 or 4 ?</p>