title: Javascript .replaceAll() is not a function type error
body: <p>The documentation page: <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/String/replaceAll" rel="noreferrer">https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/String/replaceAll</a></p>
  <p><div class="snippet" data-lang="js" data-hide="false" data-console="true" data-babel="false">
  <div class="snippet-code">
  <pre class="snippet-code-js lang-js prettyprint-override"><code>let string = ":insertx: :insertx: :inserty: :inserty: :insertz: :insertz:";
  let newstring = string.replaceAll(":insertx:", 'hello!');</code></pre>
  </div>
  </div>
  </p>
  <p>When I run this, I receive <code>Uncaught TypeError: string.replaceAll is not a function</code>. Maybe I'm misunderstanding what a prototype is, but the function appears to be a string method that is available for use.</p>
  <p>I'm using Chrome.</p>