Can I insert specific buttons based on labels and have a fallback

Hi Zendesk Community! 

I am working on inserting buttons on all pages of our help center at the bottom of the page. It seems to be most viable to do this in scripting language. BUT I can came across a challenge with having a fallback button, if the labels do not meet the requirements. 

Logic I want to achieve is: 

1. Loop through labels 
2. Check for specific values
3. Insert buttons based on these values 
4. If the label of the article does not meet that, insert a fallback button. 

I have the 3 first steps working fine, I just can't figure out a way to achieve a fallback so I can ensure a button on all article pages. 

The short version: Any advice on how I can add a single fallback button based on article labels?

See my code for reference: 

   
      <!--Dynamically add buttons based on labels that link to commercial sites-->
      {{#if article.labels}}
        {{#each article.labels}}
              {{#is identifier 'dtc_forside'}}
                <div style="text-align:center">
                  <button type="button" onClick="javascript:window.open('#', '_blank');" class="dtcbutton">TEXT</button>
                </div>
              {{/is}}
              {{#is identifier 'dtc_checkout'}}
                <div style="text-align:center">
                  <button type="button" onClick="javascript:window.open('#', '_blank');" class="dtcbutton">TEXT</button>
                </div>
              {{/is}}
              {{#is identifier 'dtc_mittv2'}}
                <div style="text-align:center">
                  <button type="button" onClick="javascript:window.open('#', '_blank');" class="dtcbutton">TEXT</button>
                </div>
             {{/is}}
          {{/each}}
      {{/if}}