Feat: Update user validation schema to include username/email check

The validation schema will throw an error if the username or email is already found in the database.

src/requests/valdiateEmail.ts

@@ -0,0 +1,25 @@
+import APIResponseValidationSchema from '@/validation/APIResponseValidationSchema';
+import { z } from 'zod';
+
+const validateEmail = async (email: string) => {
+  const response = await fetch(`/api/users/check-email?email=${email}`);
+  const json = await response.json();
+
+  const parsed = APIResponseValidationSchema.safeParse(json);
+
+  if (!parsed.success) {
+    return false;
+  }
+
+  const parsedPayload = z
+    .object({ usernameIsTaken: z.boolean() })
+    .safeParse(parsed.data.payload);
+
+  if (!parsedPayload.success) {
+    return false;
+  }
+
+  return !parsedPayload.data.usernameIsTaken;
+};
+
+export default validateEmail;

src/requests/validateUsername.ts

@@ -0,0 +1,25 @@
+import APIResponseValidationSchema from '@/validation/APIResponseValidationSchema';
+import { z } from 'zod';
+
+const validateUsername = async (username: string) => {
+  const response = await fetch(`/api/users/check-username?username=${username}`);
+  const json = await response.json();
+
+  const parsed = APIResponseValidationSchema.safeParse(json);
+
+  if (!parsed.success) {
+    return false;
+  }
+
+  const parsedPayload = z
+    .object({ usernameIsTaken: z.boolean() })
+    .safeParse(parsed.data.payload);
+
+  if (!parsedPayload.success) {
+    return false;
+  }
+
+  return !parsedPayload.data.usernameIsTaken;
+};
+
+export default validateUsername;