diff --git a/js/src/admin/index.js b/js/src/admin/index.js
deleted file mode 100644
index c318dfa..0000000
--- a/js/src/admin/index.js
+++ /dev/null
@@ -1,20 +0,0 @@
-import app from 'flarum/admin/app';
-
-// Keeping the old flagrow settings prefix because it's easier
-const settingsPrefix = 'flagrow-html-errors.';
-const translationPrefix = 'fof-html-errors.admin.settings.';
-
-app.initializers.add('fof-html-errors', (app) => {
-  app.extensionData.for('fof-html-errors').registerSetting(function () {
-    return [403, 404, 500, 503].map((error) => (
-      <div className="Form-group">
-        <label>{app.translator.trans(translationPrefix + 'error.' + error)}</label>
-        <textarea
-          className="FormControl"
-          bidi={this.setting(settingsPrefix + 'custom' + error + 'ErrorHtml')}
-          placeholder={app.translator.trans(translationPrefix + 'placeholder.empty_for_default')}
-        ></textarea>
-      </div>
-    ));
-  });
-});
diff --git a/js/src/admin/index.tsx b/js/src/admin/index.tsx
new file mode 100644
index 0000000..08d36e8
--- /dev/null
+++ b/js/src/admin/index.tsx
@@ -0,0 +1,19 @@
+import app from 'flarum/admin/app';
+
+// Keeping the old flagrow settings prefix because it's easier
+const settingsPrefix = 'flagrow-html-errors.';
+const translationPrefix = 'fof-html-errors.admin.settings.';
+
+app.initializers.add('fof-html-errors', () => {
+  const extensionData = app.extensionData.for('fof-html-errors');
+
+  [403, 404, 500, 503].map((error) => {
+    extensionData.registerSetting({
+      setting: `${settingsPrefix}custom${error}ErrorHtml`,
+      label: app.translator.trans(`${translationPrefix}error.${error}`),
+      placeholder: app.translator.trans(`${translationPrefix}placeholder.empty_for_default`),
+      type: 'textarea',
+      rows: 10,
+    });
+  });
+});
diff --git a/js/tsconfig.json b/js/tsconfig.json
new file mode 100644
index 0000000..207c5b3
--- /dev/null
+++ b/js/tsconfig.json
@@ -0,0 +1,16 @@
+{
+  // Use Flarum's tsconfig as a starting point
+  "extends": "flarum-tsconfig",
+  // This will match all .ts, .tsx, .d.ts, .js, .jsx files in your `src` folder
+  // and also tells your Typescript server to read core's global typings for
+  // access to `dayjs` and `$` in the global namespace.
+  "include": ["src/**/*", "../vendor/flarum/core/js/dist-typings/@types/**/*"],
+  "compilerOptions": {
+    // This will output typings to `dist-typings`
+    "declarationDir": "./dist-typings",
+    "baseUrl": ".",
+    "paths": {
+      "flarum/*": ["../vendor/flarum/core/js/dist-typings/*"]
+    }
+  }
+}