MC-4189: IE11 - PageBuilder Does Not Load

- Load IE 11 using server side user agent checks
- Re-compile tinymce4.js

Author: davemacaulay

app/code/Magento/PageBuilder/Block/Adminhtml/Html/Head/BabelPolyfill.php

@@ -17,33 +17,43 @@
  */
 class BabelPolyfill extends Template
 {
+    const IE_11_USER_AGENT = 'Trident/7.0; rv:11.0';
+
     /**
      * @var \Magento\PageBuilder\Model\ConfigInterface
      */
     private $config;
 
+    /**
+     * @var \Magento\Framework\HTTP\Header
+     */
+    private $httpHeader;
+
     /**
      * @param Template\Context $context
      * @param \Magento\PageBuilder\Model\ConfigInterface $config
+     * @param \Magento\Framework\HTTP\Header $httpHeader
      * @param array $data
      */
     public function __construct(
         Template\Context $context,
         \Magento\PageBuilder\Model\ConfigInterface $config,
+        \Magento\Framework\HTTP\Header $httpHeader,
         array $data = []
     ) {
         $this->config = $config;
+        $this->httpHeader = $httpHeader;
         parent::__construct($context, $data);
     }
 
     /**
-     * Detect if Page Builder is enabled before loading the polyfill
+     * Detect if Page Builder is enabled and the user is loading the website from IE 11
      *
      * @return bool
      */
     public function shouldLoadPolyfill() : bool
     {
-        return $this->config->isEnabled();
+        return $this->config->isEnabled() && $this->isIe11();
     }
 
     /**
@@ -55,4 +65,26 @@ public function getJsUrl() : string
     {
         return $this->_assetRepo->getUrl("Magento_PageBuilder::js/resource/babel/polyfill.min.js");
     }
+
+    /**
+     * Extend the cache keys with a IE 11 flag
+     *
+     * @return array
+     */
+    public function getCacheKeyInfo() : array
+    {
+        $cacheKeys = parent::getCacheKeyInfo();
+        $cacheKeys['is_ie11'] = $this->isIe11();
+        return $cacheKeys;
+    }
+
+    /**
+     * Detect if the browser user agent contains the IE 11 user agent
+     *
+     * @return bool
+     */
+    private function isIe11() : bool
+    {
+        return strpos($this->httpHeader->getHttpUserAgent(), self::IE_11_USER_AGENT) !== false;
+    }
 }

app/code/Magento/PageBuilder/view/adminhtml/templates/html/head/babel_polyfill.phtml

@@ -7,10 +7,6 @@
 /* @var $block \Magento\PageBuilder\Block\Adminhtml\Html\Head\BabelPolyfill */
 
 if ($block->shouldLoadPolyfill()) : ?>
-<script>
-    if (/MSIE \d|Trident.*rv:/.test(navigator.userAgent)) {
-        document.write('<script src="<?= $block->escapeUrl($block->getJsUrl()) ?>"><\/script>');
-    }
-</script>
+<script src="<?= $block->escapeUrl($block->getJsUrl()) ?>"></script>
 <?php endif; ?>