title: how to create a map with unique keys from a parsed object in javascript es6/2015?
body: <p>Lets say I receive a parsed json like below:</p>
  
  <p><code>[{"a":1},{"a":2},{"a":3}]</code></p>
  
  <p>The keys are the same which is <code>a</code>. </p>
  
  <p>How do I make each <code>a</code> unique so that the map is usable?'</p>
  
  <p><strong>EDIT1</strong>:</p>
  
  <p>Results I want:</p>
  
  <pre><code>let myMap = {}; //I declare my variable
  //Then I fetch a json and parse it
  fetch(link)
      .then(function(response) {
        return response.json(); //parse the json string
      }).then(function(json) {
        myMap = json; //set it to myMap to be used
  }
  </code></pre>
  
  <p>For some reason I having duplicate keys although you guys said the json is unique. Do I have to set the json string to <code>myMap</code> first and then only parse it?</p>