diff --git a/packages/learn/src/templates/Challenges/rechallenge/transformers.js b/packages/learn/src/templates/Challenges/rechallenge/transformers.js
index 6aad460cf0..76ae12c429 100644
--- a/packages/learn/src/templates/Challenges/rechallenge/transformers.js
+++ b/packages/learn/src/templates/Challenges/rechallenge/transformers.js
@@ -82,10 +82,12 @@ function tryTransform(wrap = identity) {
   return function transformWrappedPoly(source) {
     const result = attempt(wrap, source);
     if (isError(result)) {
-      const friendlyError = `${result}`
-        .match(/[\w\W]+?\n/)[0]
-        .replace(' unknown:', '');
-      throw new Error(friendlyError);
+      console.error(result);
+      // note(Bouncey): Error thrown here to collapse the build pipeline
+      // At the minute, it will not bubble up
+      // We collapse the pipeline so the app doesn't fall over trying
+      // parse bad code (syntax/type errors etc...)
+      throw new Error();
     }
     return result;
   };
@@ -110,12 +112,7 @@ export const sassTransformer = cond([
   [stubTrue, identity]
 ]);
 
-export const _transformers = [
-  // addLoopProtectHtmlJsJsx,
-  replaceNBSP,
-  babelTransformer,
-  sassTransformer
-];
+export const _transformers = [replaceNBSP, babelTransformer, sassTransformer];
 
 export function applyTransformers(file, transformers = _transformers) {
   return transformers.reduce((obs, transformer) => {
diff --git a/packages/learn/src/templates/Challenges/redux/completion-epic.js b/packages/learn/src/templates/Challenges/redux/completion-epic.js
index c25c80c9f1..9f1992caf4 100644
--- a/packages/learn/src/templates/Challenges/redux/completion-epic.js
+++ b/packages/learn/src/templates/Challenges/redux/completion-epic.js
@@ -126,7 +126,7 @@ export default function completionEpic(action$, { getState }) {
       const { nextChallengePath, introPath, challengeType } = meta;
       const next = of(push(introPath ? introPath : nextChallengePath));
       const closeChallengeModal = of(closeModal('completion'));
-      let submitter = () => of({type: 'no-user-signed-in'});
+      let submitter = () => of({ type: 'no-user-signed-in' });
       if (
         !(challengeType in submitTypes) ||
         !(submitTypes[challengeType] in submitters)
@@ -140,7 +140,6 @@ export default function completionEpic(action$, { getState }) {
         submitter = submitters[submitTypes[challengeType]];
       }
 
-
       return submitter(type, state).pipe(
         concat(next),
         concat(closeChallengeModal),
diff --git a/packages/learn/src/templates/Challenges/redux/execute-challenge-epic.js b/packages/learn/src/templates/Challenges/redux/execute-challenge-epic.js
index f705613fa6..d85640e904 100644
--- a/packages/learn/src/templates/Challenges/redux/execute-challenge-epic.js
+++ b/packages/learn/src/templates/Challenges/redux/execute-challenge-epic.js
@@ -9,7 +9,12 @@ import {
   map,
   filter,
   pluck,
-  concat
+  concat,
+  tap,
+  catchError,
+  ignoreElements,
+  startWith,
+  delay
 } from 'rxjs/operators';
 import { ofType, combineEpics } from 'redux-observable';
 import { overEvery, isString } from 'lodash';
@@ -22,7 +27,8 @@ import {
   updateConsole,
   checkChallenge,
   updateTests,
-  disableJSOnError
+  disableJSOnError,
+  isJSEnabledSelector
 } from './';
 import { buildFromFiles, buildBackendChallenge } from '../utils/build';
 import {
@@ -49,10 +55,11 @@ function updateMainEpic(actions, { getState }, { document }) {
         ),
         debounceTime(executeDebounceTimeout),
         switchMap(() =>
-          buildFromFiles(getState(), true)
-            .map(frameMain)
-            .ignoreElements()
-            .catch(() => of({ type: 'NULL' }))
+          buildFromFiles(getState(), true).pipe(
+            map(frameMain),
+            ignoreElements(),
+            catchError(err => of(disableJSOnError(err)))
+          )
         )
       );
       return merge(buildAndFrameMain, proxyLogger.map(updateConsole));
@@ -76,40 +83,41 @@ function executeChallengeEpic(action$, { getState }, { document }) {
           const postTests = of(
             updateConsole('// tests completed'),
             checkChallenge(checkChallengePayload)
-          ).delay(250);
-          // run the tests within the test iframe
-          return runTestsInTestFrame(document, tests)
-            .flatMap(tests => {
+          ).pipe(delay(250));
+          return runTestsInTestFrame(document, tests).pipe(
+            switchMap(tests => {
               return from(tests).pipe(
                 map(({ message }) => message),
                 filter(overEvery(isString, Boolean)),
                 map(updateConsole),
                 concat(of(updateTests(tests)))
               );
-            })
-            .concat(postTests);
+            }),
+            concat(postTests)
+          );
         })
       );
       const buildAndFrameChallenge = action$.pipe(
         ofType(types.executeChallenge),
         debounceTime(executeDebounceTimeout),
-        // if isCodeLocked do not run challenges
-        // .filter(() => !codeLockedSelector(getState()))
+        filter(() => isJSEnabledSelector(getState())),
         switchMap(() => {
           const state = getState();
           const { challengeType } = challengeMetaSelector(state);
           if (challengeType === backend) {
-            return buildBackendChallenge(state)
-              .do(frameTests)
-              .ignoreElements()
-              .startWith(initConsole('// running test'))
-              .catch(err => disableJSOnError(err));
+            return buildBackendChallenge(state).pipe(
+              tap(frameTests),
+              ignoreElements(),
+              startWith(initConsole('// running test')),
+              catchError(err => of(disableJSOnError(err)))
+            );
           }
-          return buildFromFiles(state, false)
-            .do(frameTests)
-            .ignoreElements()
-            .startWith(initConsole('// running test'))
-            .catch(err => disableJSOnError(err));
+          return buildFromFiles(state, false).pipe(
+            tap(frameTests),
+            ignoreElements(),
+            startWith(initConsole('// running test')),
+            catchError(err => of(disableJSOnError(err)))
+          );
         })
       );
       return merge(buildAndFrameChallenge, challengeResults);
diff --git a/packages/learn/src/templates/Challenges/redux/index.js b/packages/learn/src/templates/Challenges/redux/index.js
index cb82dfb231..1de7ba068e 100644
--- a/packages/learn/src/templates/Challenges/redux/index.js
+++ b/packages/learn/src/templates/Challenges/redux/index.js
@@ -104,10 +104,13 @@ export const updateSuccessMessage = createAction(types.updateSuccessMessage);
 
 export const lockCode = createAction(types.lockCode);
 export const unlockCode = createAction(types.unlockCode);
-export const disableJSOnError = createAction(types.disableJSOnError, err => {
-  console.error(err);
-  return {};
-});
+export const disableJSOnError = createAction(
+  types.disableJSOnError,
+  ({ payload }) => {
+    console.error(JSON.stringify(payload));
+    return null;
+  }
+);
 export const storedCodeFound = createAction(types.storedCodeFound);
 export const noStoredCodeFound = createAction(types.noStoredCodeFound);
 
diff --git a/packages/learn/src/templates/Challenges/utils/build.js b/packages/learn/src/templates/Challenges/utils/build.js
index 5184eb1bb6..87c4b5f903 100644
--- a/packages/learn/src/templates/Challenges/utils/build.js
+++ b/packages/learn/src/templates/Challenges/utils/build.js
@@ -8,7 +8,6 @@ import {
   challengeFilesSelector,
   isJSEnabledSelector,
   challengeMetaSelector,
-  disableJSOnError,
   backendFormValuesSelector
 } from '../redux';
 import {
@@ -55,8 +54,7 @@ export function buildFromFiles(state, shouldProxyConsole) {
     ::pipe(shouldProxyConsole ? proxyLoggerTransformer : identity)
     ::pipe(jsToHtml)
     ::pipe(cssToHtml)
-    ::concatHtml(finalRequires, template)
-    .catch(err => disableJSOnError(err));
+    ::concatHtml(finalRequires, template);
 }
 
 export function buildBackendChallenge(state) {