title: How to use a value as a keyword to call a function?
body: <p>Hey I want to use the value as a keyword of a const variable along with "this".</p>
  
  <pre><code>const northAmerica = "Welcome to north america";
  
  private __onChange = (event: React.FormEvent&lt;HTMLDivElement&gt;, item: IDropdownOption): void =&gt; {
  this.setState({ mco: this.`${item.key}` });  };
  </code></pre>
  
  <p>Whenever I get the item.key = "northAmerica" I want to assign the mco to const northAmerica. Is there any way to do it.I tried using $<code>{item.key}</code> but getting an error. </p>
  
  <pre><code>error:Identifier expected.
  </code></pre>