text: const NaturalLanguageUnderstandingV1 = require('watson-developer-cloud/natural-language-understanding/v1.js');
  
  const nlu = new NaturalLanguageUnderstandingV1({
      username,
      password,
      version: '2018-04-05'
  });
  
  const params = {
      text,
      features: {
          keywords: {}
      }
  }
  
  nlu.analyze(
      params,
      (err, res) => {
          const keywords = res.keywords
      })
  