diff --git a/src/commons/assessment/AssessmentTypes.ts b/src/commons/assessment/AssessmentTypes.ts
index 2bd726f9b3..02c1b806ae 100644
--- a/src/commons/assessment/AssessmentTypes.ts
+++ b/src/commons/assessment/AssessmentTypes.ts
@@ -1,4 +1,4 @@
-import { Chapter, SourceError, Variant } from 'js-slang/dist/types';
+import { Chapter, LanguageOptions, SourceError, Variant } from 'js-slang/dist/types';
 
 import { ExternalLibrary, ExternalLibraryName } from '../application/types/ExternalTypes';
 
@@ -177,6 +177,7 @@ export type Library = {
     2?: string; // For mission control
   }>;
   moduleParams?: any;
+  languageOptions?: LanguageOptions;
 };
 
 export type Testcase = {
diff --git a/src/commons/sagas/WorkspaceSaga/helpers/blockExtraMethods.ts b/src/commons/sagas/WorkspaceSaga/helpers/blockExtraMethods.ts
index 95ec7e6fb7..a3b0f2c11f 100644
--- a/src/commons/sagas/WorkspaceSaga/helpers/blockExtraMethods.ts
+++ b/src/commons/sagas/WorkspaceSaga/helpers/blockExtraMethods.ts
@@ -1,8 +1,10 @@
 import { Context } from 'js-slang';
+import { Variant } from 'js-slang/dist/types';
 import { call } from 'redux-saga/effects';
 
 import {
   getBlockExtraMethodsString,
+  getBlockExtraMethodsStringTypedVariant,
   getDifferenceInMethods,
   getStoreExtraMethodsString
 } from '../../../utils/JsSlangHelper';
@@ -35,7 +37,10 @@ export function* blockExtraMethods(
     );
   }
 
-  const nullifier = getBlockExtraMethodsString(toBeBlocked);
+  const nullifier =
+    context.variant === Variant.TYPED
+      ? getBlockExtraMethodsStringTypedVariant(toBeBlocked)
+      : getBlockExtraMethodsString(toBeBlocked);
   const nullifierFilePath = '/nullifier.js';
   const nullifierFiles = {
     [nullifierFilePath]: nullifier
diff --git a/src/commons/sagas/WorkspaceSaga/helpers/clearContext.ts b/src/commons/sagas/WorkspaceSaga/helpers/clearContext.ts
index a12b6f3100..e1fabb6c13 100644
--- a/src/commons/sagas/WorkspaceSaga/helpers/clearContext.ts
+++ b/src/commons/sagas/WorkspaceSaga/helpers/clearContext.ts
@@ -1,6 +1,6 @@
 import { Context } from 'js-slang';
 import { defineSymbol } from 'js-slang/dist/createContext';
-import { Variant } from 'js-slang/dist/types';
+import { LanguageOptions, Variant } from 'js-slang/dist/types';
 import { put, select, take } from 'redux-saga/effects';
 import WorkspaceActions from 'src/commons/workspace/WorkspaceActions';
 
@@ -10,18 +10,20 @@ import { actions } from '../../../utils/ActionsHelper';
 import { WorkspaceLocation } from '../../../workspace/WorkspaceTypes';
 
 export function* clearContext(workspaceLocation: WorkspaceLocation, entrypointCode: string) {
-  const [chapter, symbols, externalLibraryName, globals, variant]: [
+  const [chapter, symbols, externalLibraryName, globals, variant, languageOptions]: [
     number,
     string[],
     ExternalLibraryName,
     Array<[string, any]>,
-    Variant
+    Variant,
+    LanguageOptions
   ] = yield select((state: OverallState) => [
     state.workspaces[workspaceLocation].context.chapter,
     state.workspaces[workspaceLocation].context.externalSymbols,
     state.workspaces[workspaceLocation].externalLibrary,
     state.workspaces[workspaceLocation].globals,
-    state.workspaces[workspaceLocation].context.variant
+    state.workspaces[workspaceLocation].context.variant,
+    state.workspaces[workspaceLocation].context.languageOptions
   ]);
 
   const library = {
@@ -31,7 +33,8 @@ export function* clearContext(workspaceLocation: WorkspaceLocation, entrypointCo
       name: externalLibraryName,
       symbols
     },
-    globals
+    globals,
+    languageOptions
   };
 
   // Clear the context, with the same chapter and externalSymbols as before.
diff --git a/src/commons/sagas/WorkspaceSaga/helpers/evalEditor.ts b/src/commons/sagas/WorkspaceSaga/helpers/evalEditor.ts
index 4e7cb11ca2..225805e51a 100644
--- a/src/commons/sagas/WorkspaceSaga/helpers/evalEditor.ts
+++ b/src/commons/sagas/WorkspaceSaga/helpers/evalEditor.ts
@@ -1,4 +1,5 @@
 import { FSModule } from 'browserfs/dist/node/core/FS';
+import { Variant } from 'js-slang/dist/types';
 import { call, put, select, StrictEffect } from 'redux-saga/effects';
 import WorkspaceActions from 'src/commons/workspace/WorkspaceActions';
 
@@ -93,19 +94,28 @@ export function* evalEditorSaga(
       const prependFiles = {
         [prependFilePath]: prepend
       };
-      yield call(
-        evalCodeSaga,
-        prependFiles,
-        prependFilePath,
-        elevatedContext,
-        execTime,
-        workspaceLocation,
-        EVAL_SILENT
-      );
+      if (context.variant !== Variant.TYPED) {
+        yield call(
+          evalCodeSaga,
+          prependFiles,
+          prependFilePath,
+          elevatedContext,
+          execTime,
+          workspaceLocation,
+          EVAL_SILENT
+        );
+      }
+
       // Block use of methods from privileged context
       yield* blockExtraMethods(elevatedContext, context, execTime, workspaceLocation);
     }
 
+    if (context.variant === Variant.TYPED) {
+      // Prepend was multi-line, now we need to split them by \n and join them
+      // This is to avoid extra lines in the editor which affects the error message location
+      const prependSingleLine = prepend.split('\n').join('');
+      files[entrypointFilePath] = prependSingleLine + files[entrypointFilePath];
+    }
     yield call(
       evalCodeSaga,
       files,
diff --git a/src/commons/utils/JsSlangHelper.ts b/src/commons/utils/JsSlangHelper.ts
index ab88e89db8..d6c92eaeef 100644
--- a/src/commons/utils/JsSlangHelper.ts
+++ b/src/commons/utils/JsSlangHelper.ts
@@ -1,6 +1,13 @@
 /* tslint:disable: ban-types*/
 import createSlangContext, { defineBuiltin, importBuiltins } from 'js-slang/dist/createContext';
-import { Chapter, Context, CustomBuiltIns, Value, Variant } from 'js-slang/dist/types';
+import {
+  Chapter,
+  Context,
+  CustomBuiltIns,
+  LanguageOptions,
+  Value,
+  Variant
+} from 'js-slang/dist/types';
 import { stringify } from 'js-slang/dist/utils/stringify';
 import { difference, keys } from 'lodash';
 import CseMachine from 'src/features/cseMachine/CseMachine';
@@ -148,9 +155,17 @@ export function createContext<T>(
   chapter: Chapter,
   externals: string[],
   externalContext: T,
-  variant: Variant = Variant.DEFAULT
+  variant: Variant = Variant.DEFAULT,
+  languageOptions?: LanguageOptions
 ) {
-  return createSlangContext<T>(chapter, variant, externals, externalContext, externalBuiltIns);
+  return createSlangContext<T>(
+    chapter,
+    variant,
+    languageOptions,
+    externals,
+    externalContext,
+    externalBuiltIns
+  );
 }
 
 // Assumes that the grader doesn't need additional external libraries apart from the standard
@@ -166,6 +181,7 @@ function loadStandardLibraries(proxyContext: Context, customBuiltIns: CustomBuil
 // intercepts reads from the underlying Context and returns desired values
 export function makeElevatedContext(context: Context) {
   function ProxyFrame() {}
+
   ProxyFrame.prototype = context.runtime.environments[0].head;
   // eslint-disable-next-line @typescript-eslint/ban-ts-comment
   // @ts-ignore
@@ -243,3 +259,13 @@ export function getBlockExtraMethodsString(toRemove: string[]) {
     )
     .join('\n');
 }
+
+export function getBlockExtraMethodsStringTypedVariant(toRemove: string[]) {
+  return toRemove
+    .map(x =>
+      x === 'makeUndefinedErrorFunction'
+        ? ''
+        : `const ${x} : string = makeUndefinedErrorFunction('${x}');`
+    )
+    .join('\n');
+}
diff --git a/src/commons/workspace/WorkspaceReducer.ts b/src/commons/workspace/WorkspaceReducer.ts
index a4cc98a8c3..57f6e557d0 100644
--- a/src/commons/workspace/WorkspaceReducer.ts
+++ b/src/commons/workspace/WorkspaceReducer.ts
@@ -98,7 +98,8 @@ const newWorkspaceReducer = createReducer(defaultWorkspaceManager, builder => {
             action.payload.library.chapter,
             action.payload.library.external.symbols,
             workspaceLocation,
-            action.payload.library.variant
+            action.payload.library.variant,
+            action.payload.library.languageOptions
           ),
           globals: action.payload.library.globals,
           externalLibrary: action.payload.library.external.name