title: How to get a specific key from Map object in javascript
body: <p>I have a map object and I would like to get the value of a specific key ( the value of key it self ) from the Map object 
  let say we want to get 'correct' </p>
  
  <p>we can get the values of 'correct' key  by :
   <code>question.get('correct') // return 3</code> 
  but i want : 
   <code>someCode //return 'correct'</code></p>
  
  <pre><code>const question = new Map();
  
  question.set('question','What is the latest version of javasript ?')
  question.set(1,'es4')
  question.set(2,'es5')
  question.set(3,'es6')
  question.set('correct',3)
  question.set(true , 'correct Answer');
  question.set(false , 'wrong Answer')
  
  </code></pre>