How can I replace dmx-text with a condition?

Hi,

I would like to replace dmx-text with a condition.
For instance, if entrytypefee ==0, I would like to replace entrytypefee with “Free”.
I set as follows though, it didn’t work. how can I solve this?

<dd class="text-secondary" dmx-text="entrytypefee" dmx-class:stylefree="entrytypefee==0"></dd>

  .stylefree{
    visibility: hidden; 
    position: relative;
  }
  .stylefree:after{
    color: #6c757d!important;
    font-size: 14px;
    content:"Free";
  }