Support mapped schema field

.changeset/some-corners-relate.md

@@ -0,0 +1,5 @@
+---
+'better-auth-harmony': minor
+---
+
+Support mapped schema field (#31 thanks @kdcokenny)

packages/plugins/src/email/email-schema.test.ts

@@ -0,0 +1,113 @@
+import { afterAll, describe, expect, it, vi } from 'vitest';
+// eslint-disable-next-line import/no-relative-packages -- couldn't find a better way to include it
+import { getTestInstance } from '../../../../better-auth/packages/better-auth/src/test-utils/test-instance';
+import emailHarmony, { type UserWithNormalizedEmail } from '.';
+import { allEmail, allEmailSignIn, emailForget, emailSignUp } from './matchers';
+// eslint-disable-next-line import/no-relative-packages -- couldn't find a better way to include it
+import type { BetterAuthPlugin } from '../../../../better-auth/packages/better-auth/src/types';
+
+interface SQLiteDB {
+  close: () => Promise<void>;
+}
+
+describe('Mapped schema', async () => {
+  const mockSendEmail = vi.fn();
+  // eslint-disable-next-line @typescript-eslint/no-unused-vars -- false positive
+  let token = '';
+
+  const { client, db, auth } = await getTestInstance(
+    {
+      emailAndPassword: {
+        enabled: true,
+        async sendResetPassword({ url }) {
+          token = url.split('?')[0]?.split('/').pop() ?? '';
+          await mockSendEmail();
+        }
+      },
+      plugins: [
+        emailHarmony({
+          allowNormalizedSignin: true,
+          matchers: {
+            signIn: [emailForget, allEmailSignIn, emailSignUp],
+            validation: [emailForget, allEmail]
+          },
+          schema: {
+            user: {
+              fields: {
+                normalizedEmail: 'normalized_email'
+              }
+            }
+          }
+        }) as BetterAuthPlugin
+      ]
+    },
+    {
+      disableTestUser: true
+    }
+  );
+
+  afterAll(async () => {
+    // TODO: Open PR for better-auth/src/test-utils/test-instance
+    await (auth.options.database as unknown as SQLiteDB).close();
+  });
+
+  describe('signup', () => {
+    it('should normalize email', async () => {
+      const rawEmail = '[email protected]';
+      await client.signUp.email({
+        email: rawEmail,
+        password: 'new-password',
+        name: 'new-name'
+      });
+      const userYes = await db.findOne<UserWithNormalizedEmail>({
+        model: 'user',
+        where: [
+          {
+            field: 'email',
+            value: rawEmail
+          }
+        ]
+      });
+      // expect(userNo?.email).toBeUndefined();
+      expect(userYes?.email).toBe(rawEmail);
+    });
+
+    it('should reject temporary emails', async () => {
+      const rawEmail = '[email protected]';
+      const { error } = await client.signUp.email({
+        email: rawEmail,
+        password: 'new-password',
+        name: 'new-name'
+      });
+      expect(error).not.toBeNull();
+    });
+
+    it('should prevent signups with email variations', async () => {
+      const rawEmail = '[email protected]';
+      await client.signUp.email({
+        email: rawEmail,
+        password: 'new-password',
+        name: 'new-name'
+      });
+      const user = await db.findOne<UserWithNormalizedEmail>({
+        model: 'user',
+        where: [
+          {
+            field: 'normalizedEmail',
+            value: '[email protected]'
+          }
+        ]
+      });
+      expect(user?.email).toBe(rawEmail);
+
+      // Duplicate signup attempt
+      const { error } = await client.signUp.email({
+        email: '[email protected]',
+        password: 'new-password',
+        name: 'new-name'
+      });
+
+      expect(error?.status).toBe(422);
+    });
+  });
+});

packages/plugins/src/email/index.ts

@@ -11,6 +11,15 @@ export interface UserWithNormalizedEmail extends User {
   normalizedEmail?: string | null;
 }
 
+export interface EmailHarmonySchema {
+  user: {
+    fields: {
+      /** Map the normalizedEmail field name to a custom value */
+      normalizedEmail?: string;
+    };
+  };
+}
+
 export interface EmailHarmonyOptions {
   /**
    * Allow logging in with any version of the unnormalized email address. Also works for password
@@ -57,6 +66,8 @@ export interface EmailHarmonyOptions {
      */
     validation?: Matcher[];
   };
+  /** Pass the `schema` option to customize the field names */
+  schema?: EmailHarmonySchema;
 }
 
 interface Context {
@@ -84,6 +95,7 @@ const emailHarmony = ({
   allowNormalizedSignin = false,
   validator = validateEmail,
   matchers = {},
+  schema,
   normalizer = normalizeEmail
 }: EmailHarmonyOptions = {}): BetterAuthPlugin =>
   ({
@@ -126,6 +138,7 @@ const emailHarmony = ({
         fields: {
           normalizedEmail: {
             type: 'string',
+            fieldName: schema?.user.fields.normalizedEmail ?? 'normalizedEmail',
             required: false,
             unique: true,
             input: false,