From b5f42c587300c313bdebab4d364d0c7759e39752 Mon Sep 17 00:00:00 2001
From: Sunil Pai <spai@cloudflare.com>
Date: Tue, 15 Feb 2022 16:27:50 +0000
Subject: [PATCH] chore: enable `strict` in `tsconfig.json` (#456)

In the march towards full strictness, this enables `strict` in `tsconfig.json` and fixes the errors it pops up. A changeset is included because there are some subtle code changes, and we should leave a trail for them.
---
 .changeset/modern-owls-begin.md               |  7 ++
 .../src/__tests__/helpers/command-exists.d.ts |  6 ++
 .../src/__tests__/helpers/faye-websocket.d.ts |  6 ++
 .../src/__tests__/helpers/mock-bin.ts         |  5 +-
 .../src/__tests__/helpers/run-wrangler.ts     |  8 ++-
 packages/wrangler/src/__tests__/kv.test.ts    |  6 +-
 .../src/__tests__/package-manager.test.ts     |  4 +-
 .../wrangler/src/__tests__/publish.test.ts    |  2 +-
 .../wrangler/src/__tests__/secret.test.ts     |  6 +-
 packages/wrangler/src/api/worker.ts           |  5 +-
 packages/wrangler/src/cfetch/internal.ts      | 11 +++-
 packages/wrangler/src/config.ts               | 12 +++-
 packages/wrangler/src/dev.tsx                 | 14 ++--
 packages/wrangler/src/index.tsx               | 18 ++++--
 packages/wrangler/src/inspect.ts              |  6 +-
 packages/wrangler/src/pages.tsx               | 11 ++--
 packages/wrangler/src/publish.ts              |  2 +-
 packages/wrangler/src/sites.tsx               |  2 +-
 packages/wrangler/src/user.tsx                | 64 +++++++++++--------
 tsconfig.json                                 |  2 +-
 20 files changed, 132 insertions(+), 65 deletions(-)
 create mode 100644 .changeset/modern-owls-begin.md
 create mode 100644 packages/wrangler/src/__tests__/helpers/command-exists.d.ts
 create mode 100644 packages/wrangler/src/__tests__/helpers/faye-websocket.d.ts

diff --git a/.changeset/modern-owls-begin.md b/.changeset/modern-owls-begin.md
new file mode 100644
index 000000000000..89278028ba73
--- /dev/null
+++ b/.changeset/modern-owls-begin.md
@@ -0,0 +1,7 @@
+---
+"wrangler": patch
+---
+
+chore: enable `strict` in `tsconfig.json`
+
+In the march towards full strictness, this enables `strict` in `tsconfig.json` and fixes the errors it pops up. A changeset is included because there are some subtle code changes, and we should leave a trail for them.
diff --git a/packages/wrangler/src/__tests__/helpers/command-exists.d.ts b/packages/wrangler/src/__tests__/helpers/command-exists.d.ts
new file mode 100644
index 000000000000..7596c7935fb6
--- /dev/null
+++ b/packages/wrangler/src/__tests__/helpers/command-exists.d.ts
@@ -0,0 +1,6 @@
+module "command-exists" {
+  /**
+   * Detect whether a command exists on the system.
+   */
+  export default function commandExists(cmd: string): Promise<void>;
+}
diff --git a/packages/wrangler/src/__tests__/helpers/faye-websocket.d.ts b/packages/wrangler/src/__tests__/helpers/faye-websocket.d.ts
new file mode 100644
index 000000000000..145593215836
--- /dev/null
+++ b/packages/wrangler/src/__tests__/helpers/faye-websocket.d.ts
@@ -0,0 +1,6 @@
+module "faye-websocket" {
+  /**
+   * Standards-compliant WebSocket client and server.
+   */
+  export default WebSocket;
+}
diff --git a/packages/wrangler/src/__tests__/helpers/mock-bin.ts b/packages/wrangler/src/__tests__/helpers/mock-bin.ts
index 83f19bac3d15..233272683924 100644
--- a/packages/wrangler/src/__tests__/helpers/mock-bin.ts
+++ b/packages/wrangler/src/__tests__/helpers/mock-bin.ts
@@ -7,7 +7,10 @@ const nodeShebang = "#!/usr/bin/env node";
 /**
  * Create a binary file in a temp directory and make it available on the PATH.
  */
-export async function mockBinary(binaryName: string, code: string) {
+export async function mockBinary(
+  binaryName: string,
+  code: string
+): Promise<() => void> {
   // Ensure there is a directory to put the mock binary in.
   const tmpDir = resolve(mkdtempSync(".mock-binary-"));
 
diff --git a/packages/wrangler/src/__tests__/helpers/run-wrangler.ts b/packages/wrangler/src/__tests__/helpers/run-wrangler.ts
index 1fc8dbc73a1e..a59e88d4d238 100644
--- a/packages/wrangler/src/__tests__/helpers/run-wrangler.ts
+++ b/packages/wrangler/src/__tests__/helpers/run-wrangler.ts
@@ -7,8 +7,10 @@ import { normalizeSlashes, stripTimings } from "./mock-console";
 export async function runWrangler(cmd?: string) {
   try {
     await main(cmd?.split(" ") ?? []);
-  } catch (e) {
-    e.message = normalizeSlashes(stripTimings(e.message));
-    throw e;
+  } catch (err) {
+    if (err instanceof Error) {
+      err.message = normalizeSlashes(stripTimings(err.message));
+    }
+    throw err;
   }
 }
diff --git a/packages/wrangler/src/__tests__/kv.test.ts b/packages/wrangler/src/__tests__/kv.test.ts
index 69e59a9b9772..d09a48ce50ac 100644
--- a/packages/wrangler/src/__tests__/kv.test.ts
+++ b/packages/wrangler/src/__tests__/kv.test.ts
@@ -10,7 +10,7 @@ import { mockConsoleMethods } from "./helpers/mock-console";
 import { mockKeyListRequest } from "./helpers/mock-kv";
 import { runInTempDir } from "./helpers/run-in-tmp";
 import { runWrangler } from "./helpers/run-wrangler";
-import type { KVNamespaceInfo } from "../kv";
+import type { KVNamespaceInfo, NamespaceKeyInfo } from "../kv";
 
 describe("wrangler", () => {
   mockAccountId();
@@ -839,7 +839,9 @@ describe("wrangler", () => {
               "kv:key list --namespace-id some-namespace-id --limit 100"
             );
             expect(std.err).toMatchInlineSnapshot(`""`);
-            expect(JSON.parse(std.out).map((k) => k.name)).toEqual(keys);
+            expect(
+              JSON.parse(std.out).map((k: NamespaceKeyInfo) => k.name)
+            ).toEqual(keys);
             expect(requests.count).toEqual(6);
           });
         });
diff --git a/packages/wrangler/src/__tests__/package-manager.test.ts b/packages/wrangler/src/__tests__/package-manager.test.ts
index 02e79165a446..1587c1a691fc 100644
--- a/packages/wrangler/src/__tests__/package-manager.test.ts
+++ b/packages/wrangler/src/__tests__/package-manager.test.ts
@@ -151,7 +151,7 @@ describe("getPackageManager()", () => {
  * Create a fake yarn binary
  */
 function mockYarn(succeed: boolean): void {
-  let unMock;
+  let unMock: () => void;
   beforeEach(async () => {
     unMock = await mockBinary("yarn", `process.exit(${succeed ? 0 : 1})`);
   });
@@ -162,7 +162,7 @@ function mockYarn(succeed: boolean): void {
  * Create a fake npm binary
  */
 function mockNpm(succeed: boolean): void {
-  let unMock;
+  let unMock: () => void;
   beforeEach(async () => {
     unMock = await mockBinary("npm", `process.exit(${succeed ? 0 : 1})`);
   });
diff --git a/packages/wrangler/src/__tests__/publish.test.ts b/packages/wrangler/src/__tests__/publish.test.ts
index 231cad81a226..5cf914168500 100644
--- a/packages/wrangler/src/__tests__/publish.test.ts
+++ b/packages/wrangler/src/__tests__/publish.test.ts
@@ -321,7 +321,7 @@ export default{
 
       expect(std.out).toMatchInlineSnapshot(`""`);
       expect(std.err).toMatchInlineSnapshot(`
-        "A [site] definition requires a \`bucket\` field with a path to the site's public directory.
+        "AssertionError [ERR_ASSERTION]: A [site] definition requires a \`bucket\` field with a path to the site's public directory.
 
         %s
         If you think this is a bug then please create an issue at https://github.com/cloudflare/wrangler2/issues/new."
diff --git a/packages/wrangler/src/__tests__/secret.test.ts b/packages/wrangler/src/__tests__/secret.test.ts
index c39804ee0fa2..f0f6e2b047ba 100644
--- a/packages/wrangler/src/__tests__/secret.test.ts
+++ b/packages/wrangler/src/__tests__/secret.test.ts
@@ -54,7 +54,7 @@ describe("wrangler secret", () => {
       try {
         await runWrangler("secret put the-key");
       } catch (e) {
-        error = e;
+        error = e as Error;
       }
       expect(std.out).toMatchInlineSnapshot(`""`);
       expect(std.err).toMatchInlineSnapshot(`
@@ -120,7 +120,7 @@ describe("wrangler secret", () => {
       try {
         await runWrangler("secret delete the-key");
       } catch (e) {
-        error = e;
+        error = e as Error;
       }
       expect(std.out).toMatchInlineSnapshot(`""`);
       expect(std.err).toMatchInlineSnapshot(`
@@ -186,7 +186,7 @@ describe("wrangler secret", () => {
       try {
         await runWrangler("secret list");
       } catch (e) {
-        error = e;
+        error = e as Error;
       }
       expect(std.out).toMatchInlineSnapshot(`""`);
       expect(std.err).toMatchInlineSnapshot(`
diff --git a/packages/wrangler/src/api/worker.ts b/packages/wrangler/src/api/worker.ts
index fb546ac2234a..52d3fe13cc18 100644
--- a/packages/wrangler/src/api/worker.ts
+++ b/packages/wrangler/src/api/worker.ts
@@ -114,7 +114,10 @@ export interface CfDurableObjectMigrations {
   new_tag: string;
   steps: {
     new_classes?: string[];
-    renamed_classes?: string[];
+    renamed_classes?: {
+      from: string;
+      to: string;
+    }[];
     deleted_classes?: string[];
   }[];
 }
diff --git a/packages/wrangler/src/cfetch/internal.ts b/packages/wrangler/src/cfetch/internal.ts
index 1ab772cc57c8..1acc63fac86f 100644
--- a/packages/wrangler/src/cfetch/internal.ts
+++ b/packages/wrangler/src/cfetch/internal.ts
@@ -42,7 +42,9 @@ export async function fetchInternal<ResponseType>(
   }
 }
 
-function cloneHeaders(headers: HeadersInit | undefined): HeadersInit {
+function cloneHeaders(
+  headers: HeadersInit | undefined
+): Record<string, string> {
   return { ...headers };
 }
 
@@ -61,8 +63,11 @@ function requireApiToken(): string {
   return apiToken;
 }
 
-function addAuthorizationHeader(headers: HeadersInit, apiToken: string): void {
-  if (headers["Authorization"]) {
+function addAuthorizationHeader(
+  headers: Record<string, string>,
+  apiToken: string
+): void {
+  if ("Authorization" in headers) {
     throw new Error(
       "The request already specifies an authorisation header - cannot add a new one."
     );
diff --git a/packages/wrangler/src/config.ts b/packages/wrangler/src/config.ts
index ecc0e002baf0..6881a7ae2b03 100644
--- a/packages/wrangler/src/config.ts
+++ b/packages/wrangler/src/config.ts
@@ -535,7 +535,13 @@ export function normaliseAndValidateEnvironmentsConfig(config: Config) {
     );
 
     // Fall back on "inherited fields" from the config, if not specified in the environment.
-    const inheritedFields = [
+
+    type InheritedField = keyof Omit<
+      Config,
+      "env" | "migrations" | "wasm_modules" | "site" | "dev"
+    >;
+
+    const inheritedFields: InheritedField[] = [
       "name",
       "account_id",
       "workers_dev",
@@ -546,7 +552,6 @@ export function normaliseAndValidateEnvironmentsConfig(config: Config) {
       "route",
       "jsx_factory",
       "jsx_fragment",
-      "site",
       "triggers",
       "usage_model",
     ];
@@ -554,7 +559,8 @@ export function normaliseAndValidateEnvironmentsConfig(config: Config) {
     for (const inheritedField of inheritedFields) {
       if (config[inheritedField] !== undefined) {
         if (environment[inheritedField] === undefined) {
-          environment[inheritedField] = config[inheritedField]; // TODO: - shallow or deep copy?
+          (environment[inheritedField] as typeof environment[InheritedField]) =
+            config[inheritedField]; // TODO: - shallow or deep copy?
         }
       }
     }
diff --git a/packages/wrangler/src/dev.tsx b/packages/wrangler/src/dev.tsx
index 191ac6c43976..134bbf8f22f1 100644
--- a/packages/wrangler/src/dev.tsx
+++ b/packages/wrangler/src/dev.tsx
@@ -26,6 +26,7 @@ import type { CfModule, CfWorkerInit, CfScriptFormat } from "./api/worker";
 import type { Entry } from "./bundle";
 import type { AssetPaths } from "./sites";
 import type { WatchMode } from "esbuild";
+import type { ExecaChildProcess } from "execa";
 import type { DirectoryResult } from "tmp-promise";
 
 export type DevProps = {
@@ -454,7 +455,8 @@ function useCustomBuild(
   const { command, cwd, watch_dir } = props;
   useEffect(() => {
     if (!command) return;
-    let cmd, interval;
+    let cmd: ExecaChildProcess<string> | undefined,
+      interval: NodeJS.Timeout | undefined;
     console.log("running:", command);
     cmd = execaCommand(command, {
       ...(cwd && { cwd }),
@@ -467,7 +469,7 @@ function useCustomBuild(
         "all",
         (_event, filePath) => {
           console.log(`The file ${filePath} changed, restarting build...`);
-          cmd.kill();
+          cmd?.kill();
           cmd = execaCommand(command, {
             ...(cwd && { cwd }),
             shell: true,
@@ -494,7 +496,7 @@ function useCustomBuild(
       }
 
       if (fileExists === true) {
-        clearInterval(interval);
+        interval && clearInterval(interval);
         setEntry(expectedEntry);
       } else {
         const elapsed = Date.now() - startedAt;
@@ -503,8 +505,8 @@ function useCustomBuild(
           console.error(
             `⎔ Build timed out, Could not resolve ${expectedEntry.file}`
           );
-          clearInterval(interval);
-          cmd.kill();
+          interval && clearInterval(interval);
+          cmd?.kill();
         }
       }
     }, 200);
@@ -514,7 +516,7 @@ function useCustomBuild(
         cmd.kill();
         cmd = undefined;
       }
-      clearInterval(interval);
+      interval && clearInterval(interval);
       interval = undefined;
     };
   }, [command, cwd, expectedEntry, watch_dir]);
diff --git a/packages/wrangler/src/index.tsx b/packages/wrangler/src/index.tsx
index c0b8c0763bf8..19138dedff1f 100644
--- a/packages/wrangler/src/index.tsx
+++ b/packages/wrangler/src/index.tsx
@@ -111,7 +111,7 @@ ${TOML.stringify({
 
   if (configPath && "wasm_modules" in config) {
     // rewrite wasm_module paths to be absolute
-    const modules = {};
+    const modules: Record<string, string> = {};
     for (const [name, filePath] of Object.entries(config.wasm_modules || {})) {
       modules[name] = path.relative(
         process.cwd(),
@@ -332,7 +332,7 @@ export async function main(argv: string[]): Promise<void> {
           // TODO: suggest next steps?
         } catch (err) {
           throw new Error(
-            `Failed to create wrangler.toml.\n${err.message ?? err}`
+            `Failed to create wrangler.toml.\n${(err as Error).message ?? err}`
           );
         }
       }
@@ -1373,6 +1373,7 @@ export async function main(argv: string[]): Promise<void> {
             try {
               await submitSecret();
             } catch (e) {
+              // @ts-expect-error non-standard property on Error
               if (e.code === 10007) {
                 // upload a draft worker
                 await fetchResult(
@@ -1724,7 +1725,8 @@ export async function main(argv: string[]): Promise<void> {
                 id = getNamespaceId(args, config);
               } catch (e) {
                 throw new CommandLineArgsError(
-                  "Not able to delete namespace.\n" + e.message
+                  "Not able to delete namespace.\n" +
+                    ((e as Error).message ?? e)
                 );
               }
 
@@ -2140,7 +2142,9 @@ export async function main(argv: string[]): Promise<void> {
               parsedContent = JSON.parse(content);
             } catch (err) {
               throw new Error(
-                `Could not parse json from ${filename}.\n${err.message ?? err}`
+                `Could not parse json from ${filename}.\n${
+                  (err as Error).message ?? err
+                }`
               );
             }
 
@@ -2224,7 +2228,9 @@ export async function main(argv: string[]): Promise<void> {
               parsedContent = JSON.parse(content);
             } catch (err) {
               throw new Error(
-                `Could not parse json from ${filename}.\n${err.message ?? err}`
+                `Could not parse json from ${filename}.\n${
+                  (err as Error).message ?? err
+                }`
               );
             }
 
@@ -2431,7 +2437,7 @@ export async function main(argv: string[]): Promise<void> {
       console.error(""); // Just adds a bit of space
       console.error(e.message);
     } else {
-      console.error(e.message);
+      console.error(e instanceof Error ? e.message : e);
       console.error(""); // Just adds a bit of space
       console.error(
         `${fgGreenColor}%s${resetColor}`,
diff --git a/packages/wrangler/src/inspect.ts b/packages/wrangler/src/inspect.ts
index bdd6e030b43e..0f671fd2341e 100644
--- a/packages/wrangler/src/inspect.ts
+++ b/packages/wrangler/src/inspect.ts
@@ -367,7 +367,10 @@ export default function useInspector(props: InspectorProps) {
         );
         remoteWebSocket.send(event.data);
       } catch (e) {
-        if (e.message !== "WebSocket is not open: readyState 0 (CONNECTING)") {
+        if (
+          (e as Error).message !==
+          "WebSocket is not open: readyState 0 (CONNECTING)"
+        ) {
           /**
            * ^ this just means we haven't opened a websocket yet
            * usually happens until there's at least one request
@@ -587,6 +590,7 @@ function logConsoleMessage(evt: Protocol.Runtime.ConsoleAPICalledEvent): void {
   const method = mapConsoleAPIMessageTypeToConsoleMethod[evt.type];
 
   if (method in console) {
+    // @ts-expect-error - we know this is a valid method
     // eslint-disable-next-line prefer-spread
     console[method].apply(console, args);
   } else {
diff --git a/packages/wrangler/src/pages.tsx b/packages/wrangler/src/pages.tsx
index 5922905549ef..31747c74a485 100644
--- a/packages/wrangler/src/pages.tsx
+++ b/packages/wrangler/src/pages.tsx
@@ -795,8 +795,8 @@ export const pages: BuilderCallback<unknown, unknown> = (yargs) => {
 
         let miniflareArgs: MiniflareOptions = {};
 
-        let scriptReadyResolve;
-        const scriptReadyPromise = new Promise(
+        let scriptReadyResolve: () => void;
+        const scriptReadyPromise = new Promise<void>(
           (resolve) => (scriptReadyResolve = resolve)
         );
 
@@ -830,7 +830,8 @@ export const pages: BuilderCallback<unknown, unknown> = (yargs) => {
             scriptPath,
           };
         } else {
-          scriptReadyResolve();
+          // eslint-disable-next-line @typescript-eslint/no-non-null-assertion
+          scriptReadyResolve!();
 
           const scriptPath =
             directory !== undefined
@@ -900,7 +901,7 @@ export const pages: BuilderCallback<unknown, unknown> = (yargs) => {
 
           // env.ASSETS.fetch
           serviceBindings: {
-            async ASSETS(request) {
+            async ASSETS(request: Request) {
               if (proxyPort) {
                 try {
                   const url = new URL(request.url);
@@ -962,7 +963,7 @@ export const pages: BuilderCallback<unknown, unknown> = (yargs) => {
             miniflare.dispose().catch((err) => miniflare.log.error(err));
           });
         } catch (e) {
-          miniflare.log.error(e);
+          miniflare.log.error(e as Error);
           EXIT("Could not start Miniflare.", 1);
         }
       }
diff --git a/packages/wrangler/src/publish.ts b/packages/wrangler/src/publish.ts
index c802710b69d7..6488f1adcae6 100644
--- a/packages/wrangler/src/publish.ts
+++ b/packages/wrangler/src/publish.ts
@@ -222,7 +222,7 @@ export default async function publish(props: Props): Promise<void> {
         type: bundleType,
       },
       bindings,
-      ...(migrations && { migrations }),
+      migrations,
       modules,
       compatibility_date: config.compatibility_date,
       compatibility_flags: config.compatibility_flags,
diff --git a/packages/wrangler/src/sites.tsx b/packages/wrangler/src/sites.tsx
index 5d5e062c651e..883e4f918b2b 100644
--- a/packages/wrangler/src/sites.tsx
+++ b/packages/wrangler/src/sites.tsx
@@ -129,7 +129,7 @@ export async function syncAssets(
   const result = await listNamespaceKeys(accountId, namespace);
   const keys = new Set(result.map((x) => x.name));
 
-  const manifest = {};
+  const manifest: Record<string, string> = {};
   const upload: {
     key: string;
     value: string;
diff --git a/packages/wrangler/src/user.tsx b/packages/wrangler/src/user.tsx
index e03b6614edc1..0e38649e1d2e 100644
--- a/packages/wrangler/src/user.tsx
+++ b/packages/wrangler/src/user.tsx
@@ -222,6 +222,7 @@ import React from "react";
 import { fetch } from "undici";
 import { CF_API_BASE_URL } from "./cfetch";
 import openInBrowser from "./open-in-browser";
+import type { Item as SelectInputItem } from "ink-select-input/build/SelectInput";
 import type { ParsedUrlQuery } from "node:querystring";
 import type { Response } from "undici";
 
@@ -276,14 +277,14 @@ const Scopes = {
  *
  * "offline_access" is automatically included.
  */
-type Scope = keyof typeof Scopes | "offline_access";
+type Scope = keyof typeof Scopes;
 
 const ScopeKeys = Object.keys(Scopes) as Scope[];
 
 export function validateScopeKeys(
   scopes: string[]
 ): scopes is typeof ScopeKeys {
-  return scopes.every((scope) => Scopes[scope]);
+  return scopes.every((scope) => scope in Scopes);
 }
 
 const CLIENT_ID = "54d11594-84e4-41aa-b438-e81b8fa78ee7";
@@ -561,6 +562,7 @@ export async function getAuthURL(scopes = ScopeKeys): Promise<string> {
     `?response_type=code&` +
     `client_id=${encodeURIComponent(CLIENT_ID)}&` +
     `redirect_uri=${encodeURIComponent(CALLBACK_URL)}&` +
+    // @ts-expect-error we add offline_access manually
     `scope=${encodeURIComponent(scopes.concat("offline_access").join(" "))}&` +
     `state=${stateQueryParam}&` +
     `code_challenge=${encodeURIComponent(codeChallenge)}&` +
@@ -568,6 +570,17 @@ export async function getAuthURL(scopes = ScopeKeys): Promise<string> {
   );
 }
 
+type TokenResponse =
+  | {
+      access_token: string;
+      expires_in: number;
+      refresh_token: string;
+      scope: string;
+    }
+  | {
+      error: string;
+    };
+
 /**
  * Refresh an access token from the remote service.
  */
@@ -592,13 +605,12 @@ async function exchangeRefreshTokenForAccessToken(): Promise<AccessContext> {
     throw await response.json();
   } else {
     try {
-      const json = await response.json();
-      const { access_token, expires_in, refresh_token, scope } = json as {
-        access_token: string;
-        expires_in: number;
-        refresh_token: string;
-        scope: string;
-      };
+      const json = (await response.json()) as TokenResponse;
+      if ("error" in json) {
+        throw json.error;
+      }
+
+      const { access_token, expires_in, refresh_token, scope } = json;
       let scopes: Scope[] = [];
 
       const accessToken: AccessToken = {
@@ -626,20 +638,24 @@ async function exchangeRefreshTokenForAccessToken(): Promise<AccessContext> {
         refreshToken: LocalState.refreshToken,
       };
       return accessContext;
-    } catch (err) {
-      const error = err?.error || "There was a network error.";
+    } catch (error) {
       switch (error) {
         case "invalid_grant":
-          console.log(
+          console.warn(
             "Expired! Auth code or refresh token needs to be renewed."
           );
           // alert("Redirecting to auth server to obtain a new auth grant code.");
           // TODO: return refreshAuthCodeOrRefreshToken();
           break;
         default:
+          console.error(error);
           break;
       }
-      throw toErrorClass(error);
+      if (typeof error === "string") {
+        throw toErrorClass(error);
+      } else {
+        throw error;
+      }
     }
   }
 }
@@ -680,13 +696,11 @@ async function exchangeAuthCodeForAccessToken(): Promise<AccessContext> {
     }
     throw toErrorClass(error);
   }
-  const json = await response.json();
-  const { access_token, expires_in, refresh_token, scope } = json as {
-    access_token: string;
-    expires_in: number;
-    refresh_token: string;
-    scope: string;
-  };
+  const json = (await response.json()) as TokenResponse;
+  if ("error" in json) {
+    throw new Error(json.error);
+  }
+  const { access_token, expires_in, refresh_token, scope } = json;
   let scopes: Scope[] = [];
   LocalState.hasAuthCodeBeenExchangedForAccessToken = true;
 
@@ -805,8 +819,8 @@ export async function loginOrRefreshIfRequired(): Promise<boolean> {
 export async function login(props?: LoginProps): Promise<boolean> {
   const urlToOpen = await getAuthURL(props?.scopes);
   await openInBrowser(urlToOpen);
-  let server;
-  let loginTimeoutHandle;
+  let server: http.Server;
+  let loginTimeoutHandle: NodeJS.Timeout;
   const timerPromise = new Promise<boolean>((resolve) => {
     loginTimeoutHandle = setTimeout(() => {
       console.error(
@@ -847,7 +861,7 @@ export async function login(props?: LoginProps): Promise<boolean> {
               });
               console.log(
                 "Error: Consent denied. You must grant consent to Wrangler in order to login. If you don't want to do this consider passing an API token with CF_API_TOKEN variable"
-              ); // TODO: implement wrangler config lol
+              );
 
               return;
             } else {
@@ -939,7 +953,7 @@ export async function logout(): Promise<void> {
 export function listScopes(): void {
   throwIfNotInitialised();
   console.log("💁 Available scopes:");
-  const data = ScopeKeys.map((scope) => ({
+  const data = ScopeKeys.map((scope: keyof typeof Scopes) => ({
     Scope: scope,
     Description: Scopes[scope],
   }));
@@ -1001,7 +1015,7 @@ type ChooseAccountItem = {
 };
 export function ChooseAccount(props: {
   accounts: ChooseAccountItem[];
-  onSelect: (item) => void;
+  onSelect: (item: SelectInputItem<ChooseAccountItem>) => void;
 }) {
   return (
     <>
diff --git a/tsconfig.json b/tsconfig.json
index 732557e3d865..a0f94d5abe4e 100644
--- a/tsconfig.json
+++ b/tsconfig.json
@@ -8,7 +8,7 @@
     "noEmit": true,
     "lib": ["esnext"],
     "incremental": true,
-    "strictNullChecks": true,
+    "strict": true,
     "skipLibCheck": true
   },
   "exclude": ["node_modules/"]