title: Assignment to read-only properties is not allowed in strict mode IE11
body: <p>I have been told by IE11 that <code>var self = this</code> is a read-only variable... Yet I am not assigning anything to it after its declaration point. The only variable is height that is changing. Even though, i would be able to change it when using <code>var</code></p>
  
  <p>'use strict';</p>
  
  <pre><code>    var onDocumentLoad = require('fe-client-utils/src/dom/onDocumentLoad');
      var onOrientationChange = require('fe-client-utils/src/dom/onOrientationChange');
  
      var faPageHeight = function () {
  
      };
  
      var FA = {
          init: function () {
              this.faAddons = document.querySelector('.fa-addons');
              this.faFooter = document.querySelector('.fa-footer');
              this.extraWideChild = document.querySelector('.extraWide &gt; div');
              this.extraWide = document.querySelector('.extraWide');
              this.faPages = document.querySelector('.fa-pages');
              this.pageContent = document.getElementById('page-content');
              this.faPageItems =  document.querySelectorAll('.fa-page');
              this.moveElements();
              this.faPageHeight();
          },
          faPageHeight: function () {
              var height = 0;
              var self = this;
  
              Object.keys(self.faPageItems).forEach(function (item, index) {
                  height += self.faPageItems[item].offsetHeight;
              });
  
              height += 150;
              this.extraWideChild.style.height = height+'px';
          },
          moveElements: function () {
              this.faAddons.style = '';
  
              this.pageContent.appendChild(this.faAddons);
              this.pageContent.appendChild(this.faFooter);
  
              this.faFooter.style.display = 'block';
          }
      }
  
      onDocumentLoad(function () {
          FA.init();
      });
  
      onOrientationChange(function () {
          FA.faPageHeight();
      });
  </code></pre>
  
  <p><a href="https://i.stack.imgur.com/Q74Mf.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/Q74Mf.png" alt="enter image description here"></a></p>
  
  <p>I get the following error <code>SCRIPT5045: Assignment to read-only properties is not allowed in strict mode</code> </p>
  
  <p>According to <a href="https://msdn.microsoft.com/en-us/library/br230269(v=vs.94).aspx" rel="nofollow noreferrer">Microsoft</a> you should not be able to re-write a  read-only property. I don't believe I am. So why do I get the error?</p>
  
  <blockquote>
    <ul>
    <li>Read-only property</li>
    <li>Writing to a read-only property</li>
    <li>SCRIPT5045: Assignment to read-only properties is not allowed in strict mode</li>
    <li>JavaScript</li>
    <li><code>var testObj = Object.defineProperties({}, {
        prop1: {
            value: 10,
            writable: false // by default
        },
        prop2: {
            get: function () {
            }
        }
    });
    testObj.prop1 = 20; 
    testObj.prop2 = 30;</code></li>
    </ul>
  </blockquote>