title: ngStyle with a function call not working in IE
body: <p>in an angular 4 application i have styles like below</p>
  
  <pre><code>[ngStyle]="{'border': getInterleaveColor(i)}"
  </code></pre>
  
  <p>and the function </p>
  
  <pre><code> getInterleaveColor(auditNumber) {
      var borderProperties = '2px solid';
      if (auditNumber % 2 == 0)
          return borderProperties + '#0078D2';
      else
          return borderProperties + '#00B989';
  }
  </code></pre>
  
  <p>is working fine in chrome but not working in IE. </p>