diff --git a/__tests__/frontend/basic.spec.ts b/__tests__/frontend/basic.spec.ts
index 0d610aa1..e02167d1 100644
--- a/__tests__/frontend/basic.spec.ts
+++ b/__tests__/frontend/basic.spec.ts
@@ -7,7 +7,7 @@ test("works with basic configuration", async ({ page }) => {
   const getCalls = await setup(page);
 
   await page.evaluate(() => {
-    window._endpointStubs.listSharedDrives = [
+    window._endpointStubs["listSharedDrives"] = [
       {
         status: "success",
         value: { response: [], status: "success" },
@@ -17,7 +17,7 @@ test("works with basic configuration", async ({ page }) => {
         value: { response: [], status: "success" },
       },
     ];
-    window._endpointStubs.move = [
+    window._endpointStubs["move"] = [
       {
         status: "success",
         value: { response: { errors: [] }, status: "success" },
diff --git a/__tests__/frontend/configuration.spec.ts b/__tests__/frontend/configuration.spec.ts
index 81c12151..bb5a5a07 100644
--- a/__tests__/frontend/configuration.spec.ts
+++ b/__tests__/frontend/configuration.spec.ts
@@ -7,7 +7,7 @@ test("works with copy configuration", async ({ page }) => {
   const getCalls = await setup(page);
 
   await page.evaluate(() => {
-    window._endpointStubs.listSharedDrives = [
+    window._endpointStubs["listSharedDrives"] = [
       {
         status: "success",
         value: { response: [], status: "success" },
@@ -17,7 +17,7 @@ test("works with copy configuration", async ({ page }) => {
         value: { response: [], status: "success" },
       },
     ];
-    window._endpointStubs.move = [
+    window._endpointStubs["move"] = [
       {
         status: "success",
         value: { response: { errors: [] }, status: "success" },
@@ -53,7 +53,7 @@ test("works with merge configuration", async ({ page }) => {
   const getCalls = await setup(page);
 
   await page.evaluate(() => {
-    window._endpointStubs.listSharedDrives = [
+    window._endpointStubs["listSharedDrives"] = [
       {
         status: "success",
         value: { response: [], status: "success" },
@@ -63,7 +63,7 @@ test("works with merge configuration", async ({ page }) => {
         value: { response: [], status: "success" },
       },
     ];
-    window._endpointStubs.move = [
+    window._endpointStubs["move"] = [
       {
         status: "success",
         value: { response: { errors: [] }, status: "success" },
diff --git a/__tests__/frontend/destination-selection-api-error.spec.ts b/__tests__/frontend/destination-selection-api-error.spec.ts
index 31444ef4..123bfeda 100644
--- a/__tests__/frontend/destination-selection-api-error.spec.ts
+++ b/__tests__/frontend/destination-selection-api-error.spec.ts
@@ -9,13 +9,13 @@ test("handles raw errors in source folder selection gracefully", async ({
   await setup(page);
 
   await page.evaluate(() => {
-    window._endpointStubs.listFolders = [
+    window._endpointStubs["listFolders"] = [
       {
         status: "success",
         value: { status: "error", type: "DriveAPIError" },
       },
     ];
-    window._endpointStubs.listSharedDrives = [
+    window._endpointStubs["listSharedDrives"] = [
       {
         status: "success",
         value: {
diff --git a/__tests__/frontend/destination-selection-invalid-parameter-error.spec.ts b/__tests__/frontend/destination-selection-invalid-parameter-error.spec.ts
index 7c83ee7f..5ba54e10 100644
--- a/__tests__/frontend/destination-selection-invalid-parameter-error.spec.ts
+++ b/__tests__/frontend/destination-selection-invalid-parameter-error.spec.ts
@@ -9,13 +9,13 @@ test("handles raw errors in source folder selection gracefully", async ({
   await setup(page);
 
   await page.evaluate(() => {
-    window._endpointStubs.listFolders = [
+    window._endpointStubs["listFolders"] = [
       {
         status: "success",
         value: { status: "error", type: "invalidParameter" },
       },
     ];
-    window._endpointStubs.listSharedDrives = [
+    window._endpointStubs["listSharedDrives"] = [
       {
         status: "success",
         value: {
diff --git a/__tests__/frontend/destination-selection-unhandled-error.spec.ts b/__tests__/frontend/destination-selection-unhandled-error.spec.ts
index fa529111..c017266e 100644
--- a/__tests__/frontend/destination-selection-unhandled-error.spec.ts
+++ b/__tests__/frontend/destination-selection-unhandled-error.spec.ts
@@ -9,13 +9,13 @@ test("handles raw errors in source folder selection gracefully", async ({
   await setup(page);
 
   await page.evaluate(() => {
-    window._endpointStubs.listFolders = [
+    window._endpointStubs["listFolders"] = [
       {
         status: "failure",
         value: new Error("ERROR MESSAGE"),
       },
     ];
-    window._endpointStubs.listSharedDrives = [
+    window._endpointStubs["listSharedDrives"] = [
       {
         status: "success",
         value: {
diff --git a/__tests__/frontend/destination-selection-unknown-error.spec.ts b/__tests__/frontend/destination-selection-unknown-error.spec.ts
index 749df106..a8b427c6 100644
--- a/__tests__/frontend/destination-selection-unknown-error.spec.ts
+++ b/__tests__/frontend/destination-selection-unknown-error.spec.ts
@@ -9,13 +9,13 @@ test("handles raw errors in source folder selection gracefully", async ({
   await setup(page);
 
   await page.evaluate(() => {
-    window._endpointStubs.listFolders = [
+    window._endpointStubs["listFolders"] = [
       {
         status: "success",
         value: { status: "error", type: "unknown" },
       },
     ];
-    window._endpointStubs.listSharedDrives = [
+    window._endpointStubs["listSharedDrives"] = [
       {
         status: "success",
         value: {
diff --git a/__tests__/frontend/move-api-error.spec.ts b/__tests__/frontend/move-api-error.spec.ts
index a73f667f..f3a097ba 100644
--- a/__tests__/frontend/move-api-error.spec.ts
+++ b/__tests__/frontend/move-api-error.spec.ts
@@ -7,7 +7,7 @@ test("works with an API error", async ({ page }) => {
   await setup(page);
 
   await page.evaluate(() => {
-    window._endpointStubs.listSharedDrives = [
+    window._endpointStubs["listSharedDrives"] = [
       {
         status: "success",
         value: { response: [], status: "success" },
@@ -17,7 +17,7 @@ test("works with an API error", async ({ page }) => {
         value: { response: [], status: "success" },
       },
     ];
-    window._endpointStubs.move = [
+    window._endpointStubs["move"] = [
       {
         status: "success",
         value: { status: "error", type: "DriveAPIError" },
diff --git a/__tests__/frontend/move-folders-equal-error.spec.ts b/__tests__/frontend/move-folders-equal-error.spec.ts
index 203e5a0c..c1e80d48 100644
--- a/__tests__/frontend/move-folders-equal-error.spec.ts
+++ b/__tests__/frontend/move-folders-equal-error.spec.ts
@@ -9,7 +9,7 @@ test("works with source and destination folders being equal", async ({
   await setup(page);
 
   await page.evaluate(() => {
-    window._endpointStubs.listSharedDrives = [
+    window._endpointStubs["listSharedDrives"] = [
       {
         status: "success",
         value: { response: [], status: "success" },
@@ -19,7 +19,7 @@ test("works with source and destination folders being equal", async ({
         value: { response: [], status: "success" },
       },
     ];
-    window._endpointStubs.move = [
+    window._endpointStubs["move"] = [
       {
         status: "success",
         value: { status: "error", type: "sourceEqualsDestination" },
diff --git a/__tests__/frontend/move-invalid-parameter-error.spec.ts b/__tests__/frontend/move-invalid-parameter-error.spec.ts
index ef1b6105..8d683b3a 100644
--- a/__tests__/frontend/move-invalid-parameter-error.spec.ts
+++ b/__tests__/frontend/move-invalid-parameter-error.spec.ts
@@ -7,7 +7,7 @@ test("works with an API error", async ({ page }) => {
   await setup(page);
 
   await page.evaluate(() => {
-    window._endpointStubs.listSharedDrives = [
+    window._endpointStubs["listSharedDrives"] = [
       {
         status: "success",
         value: { response: [], status: "success" },
@@ -17,7 +17,7 @@ test("works with an API error", async ({ page }) => {
         value: { response: [], status: "success" },
       },
     ];
-    window._endpointStubs.move = [
+    window._endpointStubs["move"] = [
       {
         status: "success",
         value: { status: "error", type: "invalidParameter" },
diff --git a/__tests__/frontend/move-repeat-after-timeout.spec.ts b/__tests__/frontend/move-repeat-after-timeout.spec.ts
index c8f7f1f1..5efa38d2 100644
--- a/__tests__/frontend/move-repeat-after-timeout.spec.ts
+++ b/__tests__/frontend/move-repeat-after-timeout.spec.ts
@@ -9,7 +9,7 @@ test("works with an unhandled move error", async ({ page }) => {
   await page.evaluate(() => {
     const e = new Error();
     e.name = "ScriptError";
-    window._endpointStubs.listSharedDrives = [
+    window._endpointStubs["listSharedDrives"] = [
       {
         status: "success",
         value: { response: [], status: "success" },
@@ -19,7 +19,7 @@ test("works with an unhandled move error", async ({ page }) => {
         value: { response: [], status: "success" },
       },
     ];
-    window._endpointStubs.move = [
+    window._endpointStubs["move"] = [
       {
         status: "failure",
         value: e,
diff --git a/__tests__/frontend/move-unhandled-error.spec.ts b/__tests__/frontend/move-unhandled-error.spec.ts
index 2a2f3b8d..4517dafd 100644
--- a/__tests__/frontend/move-unhandled-error.spec.ts
+++ b/__tests__/frontend/move-unhandled-error.spec.ts
@@ -7,7 +7,7 @@ test("works with an unhandled move error", async ({ page }) => {
   await setup(page);
 
   await page.evaluate(() => {
-    window._endpointStubs.listSharedDrives = [
+    window._endpointStubs["listSharedDrives"] = [
       {
         status: "success",
         value: { response: [], status: "success" },
@@ -17,7 +17,7 @@ test("works with an unhandled move error", async ({ page }) => {
         value: { response: [], status: "success" },
       },
     ];
-    window._endpointStubs.move = [
+    window._endpointStubs["move"] = [
       {
         status: "failure",
         value: new Error("ERROR MESSAGE"),
diff --git a/__tests__/frontend/move-unknown-error.spec.ts b/__tests__/frontend/move-unknown-error.spec.ts
index a5023d4e..3427888f 100644
--- a/__tests__/frontend/move-unknown-error.spec.ts
+++ b/__tests__/frontend/move-unknown-error.spec.ts
@@ -7,7 +7,7 @@ test("works with an unknown move error", async ({ page }) => {
   await setup(page);
 
   await page.evaluate(() => {
-    window._endpointStubs.listSharedDrives = [
+    window._endpointStubs["listSharedDrives"] = [
       {
         status: "success",
         value: { response: [], status: "success" },
@@ -17,7 +17,7 @@ test("works with an unknown move error", async ({ page }) => {
         value: { response: [], status: "success" },
       },
     ];
-    window._endpointStubs.move = [
+    window._endpointStubs["move"] = [
       {
         status: "success",
         value: { status: "error", type: "unknown" },
diff --git a/__tests__/frontend/navigation.spec.ts b/__tests__/frontend/navigation.spec.ts
index 64e034be..2f4c11b9 100644
--- a/__tests__/frontend/navigation.spec.ts
+++ b/__tests__/frontend/navigation.spec.ts
@@ -7,7 +7,7 @@ test("works with basic configuration", async ({ page }) => {
   const getCalls = await setup(page);
 
   await page.evaluate(() => {
-    window._endpointStubs.listSharedDrives = [
+    window._endpointStubs["listSharedDrives"] = [
       {
         status: "success",
         value: { response: [], status: "success" },
@@ -33,7 +33,7 @@ test("works with basic configuration", async ({ page }) => {
         value: { response: [], status: "success" },
       },
     ];
-    window._endpointStubs.move = [
+    window._endpointStubs["move"] = [
       {
         status: "success",
         value: { response: { errors: [] }, status: "success" },
diff --git a/__tests__/frontend/non-empty.spec.ts b/__tests__/frontend/non-empty.spec.ts
index 17ea65fa..a6e912cd 100644
--- a/__tests__/frontend/non-empty.spec.ts
+++ b/__tests__/frontend/non-empty.spec.ts
@@ -7,7 +7,7 @@ test("works with non-empty destination folder", async ({ page }) => {
   const getCalls = await setup(page);
 
   await page.evaluate(() => {
-    window._endpointStubs.listSharedDrives = [
+    window._endpointStubs["listSharedDrives"] = [
       {
         status: "success",
         value: { response: [], status: "success" },
@@ -21,7 +21,7 @@ test("works with non-empty destination folder", async ({ page }) => {
         value: { response: [], status: "success" },
       },
     ];
-    window._endpointStubs.move = [
+    window._endpointStubs["move"] = [
       {
         delay: 500,
         status: "success",
diff --git a/__tests__/frontend/source-destination-selection.spec.ts b/__tests__/frontend/source-destination-selection.spec.ts
index 2dd0c67f..48a6260d 100644
--- a/__tests__/frontend/source-destination-selection.spec.ts
+++ b/__tests__/frontend/source-destination-selection.spec.ts
@@ -7,7 +7,7 @@ test("works with folder selection", async ({ page }) => {
   const getCalls = await setup(page);
 
   await page.evaluate(() => {
-    window._endpointStubs.listFolders = [
+    window._endpointStubs["listFolders"] = [
       {
         status: "success",
         value: {
@@ -96,7 +96,7 @@ test("works with folder selection", async ({ page }) => {
         },
       },
     ];
-    window._endpointStubs.listSharedDrives = [
+    window._endpointStubs["listSharedDrives"] = [
       {
         status: "success",
         value: {
@@ -138,7 +138,7 @@ test("works with folder selection", async ({ page }) => {
         },
       },
     ];
-    window._endpointStubs.move = [
+    window._endpointStubs["move"] = [
       {
         status: "success",
         value: { response: { errors: [] }, status: "success" },
diff --git a/__tests__/frontend/source-selection-api-error.spec.ts b/__tests__/frontend/source-selection-api-error.spec.ts
index 8510dd2c..6647038f 100644
--- a/__tests__/frontend/source-selection-api-error.spec.ts
+++ b/__tests__/frontend/source-selection-api-error.spec.ts
@@ -9,7 +9,7 @@ test("handles raw errors in source folder selection gracefully", async ({
   await setup(page);
 
   await page.evaluate(() => {
-    window._endpointStubs.listSharedDrives = [
+    window._endpointStubs["listSharedDrives"] = [
       {
         status: "success",
         value: { status: "error", type: "DriveAPIError" },
diff --git a/__tests__/frontend/source-selection-invalid-parameter-error.spec.ts b/__tests__/frontend/source-selection-invalid-parameter-error.spec.ts
index ba2386b0..ea3c341d 100644
--- a/__tests__/frontend/source-selection-invalid-parameter-error.spec.ts
+++ b/__tests__/frontend/source-selection-invalid-parameter-error.spec.ts
@@ -9,7 +9,7 @@ test("handles invalid parameter errors in source folder selection gracefully", a
   await setup(page);
 
   await page.evaluate(() => {
-    window._endpointStubs.listSharedDrives = [
+    window._endpointStubs["listSharedDrives"] = [
       {
         status: "success",
         value: { status: "error", type: "invalidParameter" },
diff --git a/__tests__/frontend/source-selection-unhandled-error.spec.ts b/__tests__/frontend/source-selection-unhandled-error.spec.ts
index 48d5e684..578f306b 100644
--- a/__tests__/frontend/source-selection-unhandled-error.spec.ts
+++ b/__tests__/frontend/source-selection-unhandled-error.spec.ts
@@ -9,7 +9,7 @@ test("handles raw errors in source folder selection gracefully", async ({
   await setup(page);
 
   await page.evaluate(() => {
-    window._endpointStubs.listSharedDrives = [
+    window._endpointStubs["listSharedDrives"] = [
       {
         status: "failure",
         value: new Error("ERROR MESSAGE"),
diff --git a/__tests__/frontend/source-selection-unknown-error.spec.ts b/__tests__/frontend/source-selection-unknown-error.spec.ts
index b823510f..84642e0a 100644
--- a/__tests__/frontend/source-selection-unknown-error.spec.ts
+++ b/__tests__/frontend/source-selection-unknown-error.spec.ts
@@ -9,7 +9,7 @@ test("handles raw errors in source folder selection gracefully", async ({
   await setup(page);
 
   await page.evaluate(() => {
-    window._endpointStubs.listSharedDrives = [
+    window._endpointStubs["listSharedDrives"] = [
       {
         status: "success",
         value: { status: "error", type: "unknown" },
diff --git a/__tests__/frontend/success-with-errors.spec.ts b/__tests__/frontend/success-with-errors.spec.ts
index a2f20ec2..024c71a7 100644
--- a/__tests__/frontend/success-with-errors.spec.ts
+++ b/__tests__/frontend/success-with-errors.spec.ts
@@ -7,7 +7,7 @@ test("works and displays moving errors", async ({ page }) => {
   const getCalls = await setup(page);
 
   await page.evaluate(() => {
-    window._endpointStubs.listSharedDrives = [
+    window._endpointStubs["listSharedDrives"] = [
       {
         status: "success",
         value: { response: [], status: "success" },
@@ -17,7 +17,7 @@ test("works and displays moving errors", async ({ page }) => {
         value: { response: [], status: "success" },
       },
     ];
-    window._endpointStubs.move = [
+    window._endpointStubs["move"] = [
       {
         status: "success",
         value: {
diff --git a/playwright.config.ts b/playwright.config.ts
index 942ffa73..70666037 100644
--- a/playwright.config.ts
+++ b/playwright.config.ts
@@ -1,7 +1,7 @@
 import { defineConfig, devices } from "@playwright/test";
 
 export default defineConfig({
-  forbidOnly: process.env.CI !== undefined,
+  forbidOnly: process.env["CI"] !== undefined,
   fullyParallel: true,
   projects: [
     {
@@ -17,8 +17,8 @@ export default defineConfig({
       use: { ...devices["Desktop Safari"] },
     },
   ],
-  reporter: process.env.CI !== undefined ? "html" : "list",
-  retries: process.env.CI !== undefined ? 2 : 0,
+  reporter: process.env["CI"] !== undefined ? "html" : "list",
+  retries: process.env["CI"] !== undefined ? 2 : 0,
   testDir: "./__tests__/frontend",
   use: {
     baseURL: "http://127.0.0.1:8080",
@@ -26,9 +26,9 @@ export default defineConfig({
   },
   webServer: {
     command: "npm run start",
-    reuseExistingServer: process.env.CI === undefined,
+    reuseExistingServer: process.env["CI"] === undefined,
     url: "http://127.0.0.1:8080",
   },
   // Opt out of parallel tests on CI.
-  //workers: process.env.CI !== undefined ? 1 : undefined,
+  //workers: process.env["CI"] !== undefined ? 1 : undefined,
 });
diff --git a/src/backend/index.ts b/src/backend/index.ts
index 8749de66..667bd0c9 100644
--- a/src/backend/index.ts
+++ b/src/backend/index.ts
@@ -7,7 +7,7 @@ import { move } from "./move";
 
 declare const global: google.script.PublicEndpoints;
 
-global.doGet = doGet;
-global.listFolders = listFolders;
-global.listSharedDrives = listSharedDrives;
-global.move = move;
+global["doGet"] = doGet;
+global["listFolders"] = listFolders;
+global["listSharedDrives"] = listSharedDrives;
+global["move"] = move;
diff --git a/src/frontend/App.svelte b/src/frontend/App.svelte
index 97f2cd62..816d8a9b 100644
--- a/src/frontend/App.svelte
+++ b/src/frontend/App.svelte
@@ -120,13 +120,9 @@
     google.script.run
       .withSuccessHandler(moveSuccessHandler)
       .withFailureHandler(moveErrorHandler)
-      .move(
-        source.id,
-        destination.id,
-        copyComments,
-        mergeFolders,
-        forceNonEmpty,
-      );
+      [
+        "move"
+      ](source.id, destination.id, copyComments, mergeFolders, forceNonEmpty);
   }
 
   function showErrorDialogWithEvent(
diff --git a/src/frontend/FolderSelection.svelte b/src/frontend/FolderSelection.svelte
index 590d732b..07040774 100644
--- a/src/frontend/FolderSelection.svelte
+++ b/src/frontend/FolderSelection.svelte
@@ -65,12 +65,12 @@
       google.script.run
         .withSuccessHandler(handleSharedDriveResponse)
         .withFailureHandler(handleError)
-        .listSharedDrives();
+        ["listSharedDrives"]();
     } else {
       google.script.run
         .withSuccessHandler(handleFolderResponse)
         .withFailureHandler(handleError)
-        .listFolders(path[path.length - 1].id);
+        ["listFolders"](path[path.length - 1].id);
     }
   }
 
diff --git a/tsconfig.json b/tsconfig.json
index 9f99d8a5..90f595e5 100644
--- a/tsconfig.json
+++ b/tsconfig.json
@@ -1,16 +1,21 @@
 {
   "compilerOptions": {
+    "allowSyntheticDefaultImports": true,
+    "forceConsistentCasingInFileNames": true,
     "module": "es6",
     "moduleResolution": "node",
-    "verbatimModuleSyntax": true,
-    "allowSyntheticDefaultImports": true,
     "resolveJsonModule": true,
-    "forceConsistentCasingInFileNames": true,
+    "verbatimModuleSyntax": true,
+
+    "allowUnreachableCode": false,
+    "allowUnusedLabels": false,
+    "exactOptionalPropertyTypes": true,
     "noFallthroughCasesInSwitch": true,
+    "noImplicitOverride": true,
     "noImplicitReturns": true,
+    "noPropertyAccessFromIndexSignature": true,
     "noUnusedLocals": true,
     "noUnusedParameters": true,
-    "skipLibCheck": true,
     "strict": true
   }
 }