Added shared mailer package to remove circular dependencies between packages. (#63)

packages/mailers/core/src/index.ts

@@ -0,0 +1,37 @@
+import { z } from 'zod';
+
+const MAILER_PROVIDER = z
+  .enum(['nodemailer', 'resend'])
+  .default('nodemailer')
+  .parse(process.env.MAILER_PROVIDER);
+
+/**
+ * @description Get the mailer based on the environment variable.
+ */
+export async function getMailer() {
+  switch (MAILER_PROVIDER) {
+    case 'nodemailer':
+      return getNodemailer();
+
+    case 'resend': {
+      const { createResendMailer } = await import('@kit/resend');
+
+      return createResendMailer();
+    }
+
+    default:
+      throw new Error(`Invalid mailer: ${MAILER_PROVIDER as string}`);
+  }
+}
+
+async function getNodemailer() {
+  if (process.env.NEXT_RUNTIME === 'nodejs') {
+    const { createNodemailerService } = await import('@kit/nodemailer');
+
+    return createNodemailerService();
+  } else {
+    throw new Error(
+      'Nodemailer is not available on the edge runtime. Please use another mailer.',
+    );
+  }
+}