title: Javascript "for of" fails in IE 11
body: <p>I have the following bit of code to select and remove a d3.js node. </p>
  
  <pre><code> if (d.children) {
          for (var child of d.children) {
              if (child == node) {
                  d.children = _.without(d.children, child);
                  update(root);
                  break;
              }
          }
      }
  </code></pre>
  
  <p>This works fine in Chrome and Edge, but fails in IE-11 with missing ;. It appears to be a problem with using 'of' to loop. Has anyone else run across this issue with IE before and if so how did you resolve it?</p>