index.html

<!-- Small manual front-end test to see it all works -->
<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="UTF-8">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <meta http-equiv="X-UA-Compatible" content="ie=edge">
  <title>Translate example</title>
</head>
<body>

  <p class="greeting">
    Input the key manually in the console like this:

    <code>translate.key = 'KEYHERE';</code>

    Then call test() from the console.
  </p>

  <script src="translate.js"></script>
  <script>
    const test = async () => {
      const text = await translate('Hello world', { from: 'en', to: 'es' });
      document.querySelector('.greeting').innerText = `Hello world => ${text}`;
      console.log('Done! Look at the website :)');
    };
  </script>
</body>
</html>