diff --git a/client/src/client/workers/test-evaluator.js b/client/src/client/workers/test-evaluator.js
index 6ed8430833..ecf090431f 100644
--- a/client/src/client/workers/test-evaluator.js
+++ b/client/src/client/workers/test-evaluator.js
@@ -1,5 +1,8 @@
 /* global chai, importScripts */
-importScripts('https://cdnjs.cloudflare.com/ajax/libs/chai/4.2.0/chai.min.js');
+importScripts(
+  'https://cdnjs.cloudflare.com/ajax/libs/chai/4.2.0/chai.min.js',
+  'https://cdnjs.cloudflare.com/ajax/libs/babel-polyfill/7.0.0/polyfill.min.js'
+);
 
 const oldLog = self.console.log.bind(self.console);
 self.console.log = function proxyConsole(...args) {
diff --git a/client/src/templates/Challenges/rechallenge/builders.js b/client/src/templates/Challenges/rechallenge/builders.js
index 9adb1ec881..037fb2c66b 100644
--- a/client/src/templates/Challenges/rechallenge/builders.js
+++ b/client/src/templates/Challenges/rechallenge/builders.js
@@ -63,8 +63,8 @@ export const cssToHtml = cond([
 // ) => Observable[{ build: String, sources: Dictionary }]
 export function concatHtml(required, template, files) {
   const createBody = template ? _template(template) : defaultTemplate;
-  const sourceMap = Promise.all(files).then(
-    files => files.reduce((sources, file) => {
+  const sourceMap = Promise.all(files).then(files =>
+    files.reduce((sources, file) => {
       sources[file.name] = file.source || file.contents;
       return sources;
     }, {})
@@ -101,13 +101,18 @@ A required file can not have both a src and a link: src = ${src}, link = ${link}
     .map(source => createBody({ source }))
   );
 
+  /* eslint-disable max-len */
+  const babelPolyfillCDN =
+    'https://cdnjs.cloudflare.com/ajax/libs/babel-polyfill/7.0.0/polyfill.min.js';
+  const babelPolyfill = `<script src="${babelPolyfillCDN}" type="text/javascript"></script>`;
+  /* eslint-enable max-len */
   const frameRunner =
     '<script src="/js/frame-runner.js" type="text/javascript"></script>';
 
   return from(
-    Promise.all([head, body, frameRunner, sourceMap]).then(
-      ([head, body, frameRunner, sourceMap]) => ({
-        build: head + body + frameRunner,
+    Promise.all([head, body, babelPolyfill, frameRunner, sourceMap]).then(
+      ([head, body, babelPolyfill, frameRunner, sourceMap]) => ({
+        build: head + body + babelPolyfill + frameRunner,
         sources: sourceMap
       })
     )
diff --git a/client/src/templates/Challenges/utils/build.js b/client/src/templates/Challenges/utils/build.js
index 5aca859fb3..996833ab0f 100644
--- a/client/src/templates/Challenges/utils/build.js
+++ b/client/src/templates/Challenges/utils/build.js
@@ -15,7 +15,7 @@ import { isPromise } from './polyvinyl';
 
 const jQueryCDN =
   'https://cdn.jsdelivr.net/npm/jquery@3.3.1/dist/jquery.min.js';
-const jQuery = `<script src='${jQueryCDN}' typ='text/javascript'></script>`;
+const jQuery = `<script src='${jQueryCDN}' type='text/javascript'></script>`;
 const frameRunner =
   "<script src='/js/frame-runner.js' type='text/javascript'></script>";