title: function call with one argument in typescript
body: <p>I have this function that triggers other functions depending on the service selected:</p>
  <pre><code>const serviceCalc = (service: &quot;standard&quot; | &quot;premium&quot; | &quot;excelium&quot;) =&gt; {
  
      if (service === &quot;standard&quot;) {
          return standard();
      }
  
      if (service === &quot;premium&quot;) {
          return premium();
      }
  
      if (service === &quot;excelium&quot;) {
          return excelium();
      }
  
  }
  </code></pre>
  <p>What I'm trying to do is call the serviceCalc function but without having to specify the service that was selected in the form as a parameter of serviceCalc:</p>
  <pre><code>const commercial = () =&gt; {
      const totElevators = (document.getElementById(&quot;comminput_number-of-elevators&quot;) as HTMLInputElement); 
      const cages = totElevators.value;
      (document.getElementById('output_elevator-amount') as HTMLInputElement).value = cages;
      serviceCalc()             
  }
  </code></pre>
  <p>Any help is greatly appreciated.</p>