title: Why is the _DEFAULT const variable updated?
body: <p>I've run in to a situation that can't really explain how is this even possible.</p>
  
  <p>I made a <a href="https://plnkr.co/edit/Q7rZaDHzcrPx4sZy7P3J?p=preview" rel="nofollow noreferrer">plunker</a> for a demo.</p>
  
  <p><strong>THE CODE:</strong></p>
  
  <pre><code>angular.module('test', []).controller('TestController', function($scope) {
  
  /*
    DEFAULT CONST VARIABLE
  */
  const _DEFAULT = {
    items: [],
    name: 'Test',
    selected: null
  };
  
  /*
    TEST_CASE SCOPE VARIABLE
  */
  $scope.test_case = _DEFAULT;
  
  console.log('ON INIT DEFAULT: ', _DEFAULT);
  
  /*
    FUNCTION
  */
  $scope.clicked = () =&gt; {
    // SET TEST_CASE.SELECTED = 1
    $scope.test_case.selected = 1;
  
    // SHOW UPDATED TEST_CASE AND _DEFAULT VARIABLE
    console.log($scope.test_case, _DEFAULT);
  };
  </code></pre>
  
  <p>});</p>
  
  <p>When button is clicked (<a href="https://plnkr.co/edit/Q7rZaDHzcrPx4sZy7P3J?p=preview" rel="nofollow noreferrer">check demo</a>) we change data only in <code>$scope.test_case</code> so <strong>HOW</strong> is it possible that const variable <code>_DEFAULT</code> has the same data as <code>$scope.test_case</code> when <code>_DEFAULT</code> has never been touched or changed? </p>
  
  <p>That should be impossible or am I missing something?</p>