Convert entrypoints/sign_up to Typescript (#30106)

app/javascript/entrypoints/sign_up.ts

@@ -0,0 +1,48 @@
+import './public-path';
+import axios from 'axios';
+
+import ready from '../mastodon/ready';
+
+async function checkConfirmation() {
+  const response = await axios.get('/api/v1/emails/check_confirmation');
+
+  if (response.data) {
+    window.location.href = '/start';
+  }
+}
+
+ready(() => {
+  setInterval(() => {
+    void checkConfirmation();
+  }, 5000);
+
+  document
+    .querySelectorAll<HTMLButtonElement>('button.timer-button')
+    .forEach((button) => {
+      let counter = 30;
+
+      const container = document.createElement('span');
+
+      const updateCounter = () => {
+        container.innerText = ` (${counter})`;
+      };
+
+      updateCounter();
+
+      const countdown = setInterval(() => {
+        counter--;
+
+        if (counter === 0) {
+          button.disabled = false;
+          button.removeChild(container);
+          clearInterval(countdown);
+        } else {
+          updateCounter();
+        }
+      }, 1000);
+
+      button.appendChild(container);
+    });
+}).catch((e: unknown) => {
+  throw e;
+});