title: Angular2 change color of a cell
body: <p>Good morning,</p>
  
  <p>My question is about changing the color of a cell in a table.
  When it is empty I want it to be yellow, and when I type some value in it change to white.</p>
  
  <p>I had thought of using ngswitch, for each case, and the focus event for when I switch from one cell to another check if it is empty or has a value.</p>
  
  <p>Thanks.</p>