diff --git a/app/javascript/entrypoints/two_factor_authentication.js b/app/javascript/entrypoints/two_factor_authentication.js
deleted file mode 100644
index e77965c757..0000000000
--- a/app/javascript/entrypoints/two_factor_authentication.js
+++ /dev/null
@@ -1,119 +0,0 @@
-import * as WebAuthnJSON from '@github/webauthn-json';
-import axios from 'axios';
-
-import ready from '../mastodon/ready';
-import 'regenerator-runtime/runtime';
-
-function getCSRFToken() {
-  var CSRFSelector = document.querySelector('meta[name="csrf-token"]');
-  if (CSRFSelector) {
-    return CSRFSelector.getAttribute('content');
-  } else {
-    return null;
-  }
-}
-
-function hideFlashMessages() {
-  Array.from(document.getElementsByClassName('flash-message')).forEach(function(flashMessage) {
-    flashMessage.classList.add('hidden');
-  });
-}
-
-function callback(url, body) {
-  axios.post(url, JSON.stringify(body), {
-    headers: {
-      'Content-Type': 'application/json',
-      'Accept': 'application/json',
-      'X-CSRF-Token': getCSRFToken(),
-    },
-    credentials: 'same-origin',
-  }).then(function(response) {
-    window.location.replace(response.data.redirect_path);
-  }).catch(function(error) {
-    if (error.response.status === 422) {
-      const errorMessage = document.getElementById('security-key-error-message');
-      errorMessage.classList.remove('hidden');
-      console.error(error.response.data.error);
-    } else {
-      console.error(error);
-    }
-  });
-}
-
-ready(() => {
-  if (!WebAuthnJSON.supported()) {
-    const unsupported_browser_message = document.getElementById('unsupported-browser-message');
-    if (unsupported_browser_message) {
-      unsupported_browser_message.classList.remove('hidden');
-      document.querySelector('.btn.js-webauthn').disabled = true;
-    }
-  }
-
-
-  const webAuthnCredentialRegistrationForm = document.getElementById('new_webauthn_credential');
-  if (webAuthnCredentialRegistrationForm) {
-    webAuthnCredentialRegistrationForm.addEventListener('submit', (event) => {
-      event.preventDefault();
-
-      var nickname = event.target.querySelector('input[name="new_webauthn_credential[nickname]"]');
-      if (nickname.value) {
-        axios.get('/settings/security_keys/options')
-          .then((response) => {
-            const credentialOptions = response.data;
-
-            WebAuthnJSON.create({ 'publicKey': credentialOptions }).then((credential) => {
-              var params = { 'credential': credential, 'nickname': nickname.value };
-              callback('/settings/security_keys', params);
-            }).catch((error) => {
-              const errorMessage = document.getElementById('security-key-error-message');
-              errorMessage.classList.remove('hidden');
-              console.error(error);
-            });
-          }).catch((error) => {
-            console.error(error.response.data.error);
-          });
-      } else {
-        nickname.focus();
-      }
-    });
-  }
-
-  const webAuthnCredentialAuthenticationForm = document.getElementById('webauthn-form');
-  if (webAuthnCredentialAuthenticationForm) {
-    webAuthnCredentialAuthenticationForm.addEventListener('submit', (event) => {
-      event.preventDefault();
-
-      axios.get('sessions/security_key_options')
-        .then((response) => {
-          const credentialOptions = response.data;
-
-          WebAuthnJSON.get({ 'publicKey': credentialOptions }).then((credential) => {
-            var params = { 'user': { 'credential': credential } };
-            callback('sign_in', params);
-          }).catch((error) => {
-            const errorMessage = document.getElementById('security-key-error-message');
-            errorMessage.classList.remove('hidden');
-            console.error(error);
-          });
-        }).catch((error) => {
-          console.error(error.response.data.error);
-        });
-    });
-
-    const otpAuthenticationForm = document.getElementById('otp-authentication-form');
-
-    const linkToOtp = document.getElementById('link-to-otp');
-    linkToOtp.addEventListener('click', () => {
-      webAuthnCredentialAuthenticationForm.classList.add('hidden');
-      otpAuthenticationForm.classList.remove('hidden');
-      hideFlashMessages();
-    });
-
-    const linkToWebAuthn = document.getElementById('link-to-webauthn');
-    linkToWebAuthn.addEventListener('click', () => {
-      otpAuthenticationForm.classList.add('hidden');
-      webAuthnCredentialAuthenticationForm.classList.remove('hidden');
-      hideFlashMessages();
-    });
-  }
-});
diff --git a/app/javascript/entrypoints/two_factor_authentication.ts b/app/javascript/entrypoints/two_factor_authentication.ts
new file mode 100644
index 0000000000..981481694b
--- /dev/null
+++ b/app/javascript/entrypoints/two_factor_authentication.ts
@@ -0,0 +1,197 @@
+import * as WebAuthnJSON from '@github/webauthn-json';
+import axios, { AxiosError } from 'axios';
+
+import ready from '../mastodon/ready';
+
+import 'regenerator-runtime/runtime';
+
+type PublicKeyCredentialCreationOptionsJSON =
+  WebAuthnJSON.CredentialCreationOptionsJSON['publicKey'];
+
+function exceptionHasAxiosError(
+  error: unknown,
+): error is AxiosError<{ error: unknown }> {
+  return (
+    error instanceof AxiosError &&
+    typeof error.response?.data === 'object' &&
+    'error' in error.response.data
+  );
+}
+
+function logAxiosResponseError(error: unknown) {
+  if (exceptionHasAxiosError(error)) console.error(error);
+}
+
+function getCSRFToken() {
+  return document
+    .querySelector<HTMLMetaElement>('meta[name="csrf-token"]')
+    ?.getAttribute('content');
+}
+
+function hideFlashMessages() {
+  document.querySelectorAll('.flash-message').forEach((flashMessage) => {
+    flashMessage.classList.add('hidden');
+  });
+}
+
+async function callback(
+  url: string,
+  body:
+    | {
+        credential: WebAuthnJSON.PublicKeyCredentialWithAttestationJSON;
+        nickname: string;
+      }
+    | {
+        user: { credential: WebAuthnJSON.PublicKeyCredentialWithAssertionJSON };
+      },
+) {
+  try {
+    const response = await axios.post<{ redirect_path: string }>(
+      url,
+      JSON.stringify(body),
+      {
+        headers: {
+          'Content-Type': 'application/json',
+          Accept: 'application/json',
+          'X-CSRF-Token': getCSRFToken(),
+        },
+      },
+    );
+
+    window.location.replace(response.data.redirect_path);
+  } catch (error) {
+    if (error instanceof AxiosError && error.response?.status === 422) {
+      const errorMessage = document.getElementById(
+        'security-key-error-message',
+      );
+      errorMessage?.classList.remove('hidden');
+
+      logAxiosResponseError(error);
+    } else {
+      console.error(error);
+    }
+  }
+}
+
+async function handleWebauthnCredentialRegistration(nickname: string) {
+  try {
+    const response = await axios.get<PublicKeyCredentialCreationOptionsJSON>(
+      '/settings/security_keys/options',
+    );
+
+    const credentialOptions = response.data;
+
+    try {
+      const credential = await WebAuthnJSON.create({
+        publicKey: credentialOptions,
+      });
+
+      const params = {
+        credential: credential,
+        nickname: nickname,
+      };
+
+      await callback('/settings/security_keys', params);
+    } catch (error) {
+      const errorMessage = document.getElementById(
+        'security-key-error-message',
+      );
+      errorMessage?.classList.remove('hidden');
+      console.error(error);
+    }
+  } catch (error) {
+    logAxiosResponseError(error);
+  }
+}
+
+async function handleWebauthnCredentialAuthentication() {
+  try {
+    const response = await axios.get<PublicKeyCredentialCreationOptionsJSON>(
+      'sessions/security_key_options',
+    );
+
+    const credentialOptions = response.data;
+
+    try {
+      const credential = await WebAuthnJSON.get({
+        publicKey: credentialOptions,
+      });
+
+      const params = { user: { credential: credential } };
+      void callback('sign_in', params);
+    } catch (error) {
+      const errorMessage = document.getElementById(
+        'security-key-error-message',
+      );
+      errorMessage?.classList.remove('hidden');
+      console.error(error);
+    }
+  } catch (error) {
+    logAxiosResponseError(error);
+  }
+}
+
+ready(() => {
+  if (!WebAuthnJSON.supported()) {
+    const unsupported_browser_message = document.getElementById(
+      'unsupported-browser-message',
+    );
+    if (unsupported_browser_message) {
+      unsupported_browser_message.classList.remove('hidden');
+      const button = document.querySelector<HTMLButtonElement>(
+        'button.btn.js-webauthn',
+      );
+      if (button) button.disabled = true;
+    }
+  }
+
+  const webAuthnCredentialRegistrationForm =
+    document.querySelector<HTMLFormElement>('form#new_webauthn_credential');
+  if (webAuthnCredentialRegistrationForm) {
+    webAuthnCredentialRegistrationForm.addEventListener('submit', (event) => {
+      event.preventDefault();
+
+      if (!(event.target instanceof HTMLFormElement)) return;
+
+      const nickname = event.target.querySelector<HTMLInputElement>(
+        'input[name="new_webauthn_credential[nickname]"]',
+      );
+
+      if (nickname?.value) {
+        void handleWebauthnCredentialRegistration(nickname.value);
+      } else {
+        nickname?.focus();
+      }
+    });
+  }
+
+  const webAuthnCredentialAuthenticationForm =
+    document.getElementById('webauthn-form');
+  if (webAuthnCredentialAuthenticationForm) {
+    webAuthnCredentialAuthenticationForm.addEventListener('submit', (event) => {
+      event.preventDefault();
+      void handleWebauthnCredentialAuthentication();
+    });
+
+    const otpAuthenticationForm = document.getElementById(
+      'otp-authentication-form',
+    );
+
+    const linkToOtp = document.getElementById('link-to-otp');
+
+    linkToOtp?.addEventListener('click', () => {
+      webAuthnCredentialAuthenticationForm.classList.add('hidden');
+      otpAuthenticationForm?.classList.remove('hidden');
+      hideFlashMessages();
+    });
+
+    const linkToWebAuthn = document.getElementById('link-to-webauthn');
+    linkToWebAuthn?.addEventListener('click', () => {
+      otpAuthenticationForm?.classList.add('hidden');
+      webAuthnCredentialAuthenticationForm.classList.remove('hidden');
+      hideFlashMessages();
+    });
+  }
+}).catch((e: unknown) => {
+  throw e;
+});