title: Is there not equal ( !== ) statement in SCSS?
body: <p>How to add additional style if the value is passed? Or is there any way to do it?</p>
  
  <pre><code>@mixin link($color, $color-hover:false){
   color: $color;
   @if $color-hover !== false {
    &amp;:hover { color: $color-hover; }
   }
  }
  </code></pre>