title: Check if specific object is empty in typescript
body: <p>How to check if an object is empty?</p>
  <p>ex:</p>
  <pre><code>private brand: Brand = new Brand();
  </code></pre>
  <p>I tried:</p>
  <pre><code>if (this.brand) {
    console.log('is empty');   
  }
  </code></pre>
  <p>not working.</p>