Add: polyfill element method

js/polyfill.js

@@ -1,6 +1,53 @@
-if (!Object.entries) {
-  Object.entries = obj => Object.keys(obj).map(k => [k, obj[k]]);
-}
-if (!Object.values) {
-  Object.values = obj => Object.keys(obj).map(k => obj[k]);
-}
+'use strict';
+
+(() => {
+  if (!Object.entries) {
+    Object.entries = obj => Object.keys(obj).map(k => [k, obj[k]]);
+  }
+  if (!Object.values) {
+    Object.values = obj => Object.keys(obj).map(k => obj[k]);
+  }
+  if (typeof document === 'object') {
+    const ELEMENT_METH = {
+      append: {
+        base: [Element, Document, DocumentFragment],
+        fn: (node, frag) => {
+          node.appendChild(frag);
+        }
+      },
+      prepend: {
+        base: [Element, Document, DocumentFragment],
+        fn: (node, frag) => {
+          node.insertBefore(frag, node.firstChild);
+        }
+      },
+      before: {
+        base: [Element, CharacterData, DocumentType],
+        fn: (node, frag) => {
+          node.parentNode.insertBefore(frag, node);
+        }
+      },
+      after: {
+        base: [Element, CharacterData, DocumentType],
+        fn: (node, frag) => {
+          node.parentNode.insertBefore(frag, node.nextSibling);
+        }
+      }
+    };
+
+    for (const [key, {base, fn}] of Object.entries(ELEMENT_METH)) {
+      for (const cls of base) {
+        if (cls.prototype[key]) {
+          continue;
+        }
+        cls.prototype[key] = function (...nodes) {
+          const frag = document.createDocumentFragment();
+          for (const node of nodes) {
+            frag.appendChild(typeof node === 'string' ? document.createTextNode(node) : node);
+          }
+          fn(this, frag);
+        };
+      }
+    }
+  }
+})();