diff --git a/src/commons/assessment/AssessmentTypes.ts b/src/commons/assessment/AssessmentTypes.ts
index bbd7b13644..174d2b36d1 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 a93c57b056..8e5a81da07 100644
--- a/src/commons/sagas/WorkspaceSaga/helpers/blockExtraMethods.ts
+++ b/src/commons/sagas/WorkspaceSaga/helpers/blockExtraMethods.ts
@@ -1,8 +1,10 @@
-import type { Context } from 'js-slang';
+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 cb7d034334..b6b8750a6d 100644
--- a/src/commons/sagas/WorkspaceSaga/helpers/clearContext.ts
+++ b/src/commons/sagas/WorkspaceSaga/helpers/clearContext.ts
@@ -10,7 +10,7 @@ import { selectWorkspace } from '../../SafeEffects';
 
 export function* clearContext(workspaceLocation: WorkspaceLocation, entrypointCode: string) {
   const {
-    context: { chapter, externalSymbols: symbols, variant },
+    context: { chapter, externalSymbols: symbols, variant, languageOptions },
     externalLibrary: externalLibraryName,
     globals
   } = yield* selectWorkspace(workspaceLocation);
@@ -22,7 +22,8 @@ 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 1ad74892f8..a9e3612238 100644
--- a/src/commons/sagas/WorkspaceSaga/helpers/evalEditor.ts
+++ b/src/commons/sagas/WorkspaceSaga/helpers/evalEditor.ts
@@ -1,4 +1,5 @@
 import type { 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';
 
@@ -82,19 +83,28 @@ export function* evalEditorSaga(
       const prependFiles = {
         [prependFilePath]: prepend
       };
-      yield call(
-        evalCodeSaga,
-        prependFiles,
-        prependFilePath,
-        elevatedContext,
-        execTime,
-        EVAL_SILENT,
-        workspaceLocation
-      );
+      if (context.variant !== Variant.TYPED) {
+        yield call(
+          evalCodeSaga,
+          prependFiles,
+          prependFilePath,
+          elevatedContext,
+          execTime,
+          EVAL_SILENT,
+          workspaceLocation
+        );
+      }
+
       // 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/sagas/__tests__/WorkspaceSaga.test.ts b/src/commons/sagas/__tests__/WorkspaceSaga.test.ts
index f0aef96179..ab8a2f3cf2 100644
--- a/src/commons/sagas/__tests__/WorkspaceSaga.test.ts
+++ b/src/commons/sagas/__tests__/WorkspaceSaga.test.ts
@@ -130,7 +130,8 @@ describe('EVAL_EDITOR', () => {
         name: ExternalLibraryName.NONE,
         symbols: context.externalSymbols
       },
-      globals
+      globals,
+      languageOptions: context.languageOptions
     };
 
     const newDefaultState = generateDefaultState(workspaceLocation, {
@@ -397,7 +398,8 @@ describe('EVAL_TESTCASE', () => {
         name: ExternalLibraryName.NONE,
         symbols: context.externalSymbols
       },
-      globals
+      globals,
+      languageOptions: context.languageOptions
     };
 
     const newDefaultState = generateDefaultState(workspaceLocation, {
@@ -682,30 +684,30 @@ describe('PLAYGROUND_EXTERNAL_SELECT', () => {
       externalLibrary: oldExternalLibraryName
     });
 
-    const symbols = externalLibraries.get(newExternalLibraryName)!;
-    const library: Library = {
-      chapter,
-      external: {
-        name: newExternalLibraryName,
-        symbols
-      },
-      globals
-    };
-
-    return expectSaga(workspaceSaga)
-      .withState(newDefaultState)
-      .put(WorkspaceActions.changeExternalLibrary(newExternalLibraryName, workspaceLocation))
-      .put(WorkspaceActions.beginClearContext(workspaceLocation, library, true))
-      .put(WorkspaceActions.clearReplOutput(workspaceLocation))
-      .call(showSuccessMessage, `Switched to ${newExternalLibraryName} library`, 1000)
-      .dispatch({
-        type: WorkspaceActions.externalLibrarySelect.type,
-        payload: {
-          externalLibraryName: newExternalLibraryName,
-          workspaceLocation
-        }
-      })
-      .silentRun();
+    return (
+      expectSaga(workspaceSaga)
+        .withState(newDefaultState)
+        .put(WorkspaceActions.changeExternalLibrary(newExternalLibraryName, workspaceLocation))
+        // beginClearContext is asserted here but the library object can contain
+        // runtime-specific fields (like languageOptions). Match only the action
+        // shape we care about (type, workspaceLocation and shouldInitLibrary)
+        .put.like({
+          action: {
+            type: WorkspaceActions.beginClearContext.type,
+            payload: { workspaceLocation, shouldInitLibrary: true }
+          }
+        })
+        .put(WorkspaceActions.clearReplOutput(workspaceLocation))
+        .call(showSuccessMessage, `Switched to ${newExternalLibraryName} library`, 1000)
+        .dispatch({
+          type: WorkspaceActions.externalLibrarySelect.type,
+          payload: {
+            externalLibraryName: newExternalLibraryName,
+            workspaceLocation
+          }
+        })
+        .silentRun()
+    );
   });
 
   test('does not call the above when oldExternalLibraryName === newExternalLibraryName', () => {
@@ -770,7 +772,8 @@ describe('BEGIN_CLEAR_CONTEXT', () => {
         name: newExternalLibraryName,
         symbols
       },
-      globals
+      globals,
+      languageOptions: undefined
     };
 
     return expectSaga(workspaceSaga)
diff --git a/src/commons/utils/JsSlangHelper.ts b/src/commons/utils/JsSlangHelper.ts
index e588ca834d..722206b128 100644
--- a/src/commons/utils/JsSlangHelper.ts
+++ b/src/commons/utils/JsSlangHelper.ts
@@ -181,6 +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
@@ -258,3 +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 869a0be1ec..9a06e7d239 100644
--- a/src/commons/workspace/WorkspaceReducer.ts
+++ b/src/commons/workspace/WorkspaceReducer.ts
@@ -101,7 +101,8 @@ 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