feat(passport): ID-3764 Debounce login (#2651)

Author: haydenfowler

packages/passport/sdk/src/Passport.test.ts

@@ -583,6 +583,94 @@ describe('Passport', () => {
       expect(getUserMock).toBeCalledTimes(1);
       expect(authLoginMock).toBeCalledTimes(1);
     });
+
+    it('should debounce concurrent login calls and return the same result', async () => {
+      getUserMock.mockReturnValue(null);
+      authLoginMock.mockReturnValue(mockUserImx);
+
+      // Make multiple concurrent login calls
+      const loginPromise1 = passport.login();
+      const loginPromise2 = passport.login();
+      const loginPromise3 = passport.login();
+
+      // All promises should be the same reference
+      expect(loginPromise1).toEqual(loginPromise2);
+      expect(loginPromise2).toEqual(loginPromise3);
+
+      // Wait for all to complete
+      const [result1, result2, result3] = await Promise.all([
+        loginPromise1,
+        loginPromise2,
+        loginPromise3,
+      ]);
+
+      // All results should be the same
+      expect(result1).toEqual(mockUserImx.profile);
+      expect(result2).toEqual(mockUserImx.profile);
+      expect(result3).toEqual(mockUserImx.profile);
+
+      // AuthManager.login should only be called once despite multiple login calls
+      expect(authLoginMock).toBeCalledTimes(1);
+    });
+
+    it('should reset login promise after successful completion and allow new login calls', async () => {
+      getUserMock.mockReturnValue(null);
+      authLoginMock.mockReturnValue(mockUserImx);
+
+      // First login call
+      const firstLoginResult = await passport.login();
+      expect(firstLoginResult).toEqual(mockUserImx.profile);
+
+      // Second login call after first completes should create a new login process
+      const secondLoginResult = await passport.login();
+      expect(secondLoginResult).toEqual(mockUserImx.profile);
+
+      // AuthManager.login should be called twice (once for each login)
+      expect(authLoginMock).toBeCalledTimes(2);
+    });
+
+    it('should reset login promise after failed completion and allow new login calls', async () => {
+      const error = new Error('Login failed');
+      getUserMock.mockReturnValue(null);
+      authLoginMock.mockRejectedValue(error);
+
+      // First login call should fail
+      await expect(passport.login()).rejects.toThrow(error);
+
+      // Second login call after first fails should create a new login process
+      authLoginMock.mockReturnValue(mockUserImx);
+      const secondLoginResult = await passport.login();
+      expect(secondLoginResult).toEqual(mockUserImx.profile);
+
+      // AuthManager.login should be called twice (once for failed, once for successful)
+      expect(authLoginMock).toBeCalledTimes(2);
+    });
+
+    it('should debounce concurrent login calls even when they fail', async () => {
+      const error = new Error('Login failed');
+      getUserMock.mockReturnValue(null);
+      authLoginMock.mockRejectedValue(error);
+
+      // Make multiple concurrent login calls that will fail
+      const [loginPromise1, loginPromise2, loginPromise3] = [
+        passport.login(),
+        passport.login(),
+        passport.login(),
+      ];
+
+      // All promises should be the same reference
+      expect(loginPromise1).toEqual(loginPromise2);
+      expect(loginPromise2).toEqual(loginPromise3);
+
+      // All should reject with the same error
+      try {
+        await Promise.all([loginPromise1, loginPromise2, loginPromise3]);
+      } catch (e: unknown) {
+        expect(e).toEqual(error);
+        // AuthManager.login should only be called once despite multiple login calls
+        expect(authLoginMock).toBeCalledTimes(1);
+      }
+    });
   });
 
   describe('linkExternalWallet', () => {

packages/passport/sdk/src/Passport.ts

@@ -183,6 +183,8 @@ export class Passport {
     }, 'connectEvm', false);
   }
 
+  #loginPromise: Promise<UserProfile | null> | null = null;
+
   /**
    * Initiates the login process.
    * @param {Object} options - Login options
@@ -200,7 +202,13 @@ export class Passport {
     useSilentLogin?: boolean;
     useRedirectFlow?: boolean;
   }): Promise<UserProfile | null> {
-    return withMetricsAsync(async () => {
+    // If there's already a login in progress, return that promise
+    if (this.#loginPromise) {
+      return this.#loginPromise;
+    }
+
+    // Create and store the login promise
+    this.#loginPromise = withMetricsAsync(async () => {
       const { useCachedSession = false, useSilentLogin } = options || {};
       let user: User | null = null;
 
@@ -235,6 +243,14 @@ export class Passport {
 
       return user ? user.profile : null;
     }, 'login');
+
+    try {
+      const result = await this.#loginPromise;
+      return result;
+    } finally {
+      // Reset the login promise when the login process completes
+      this.#loginPromise = null;
+    }
   }
 
   /**