Authentication API

Authentication API

Last updated: 2025-11-15 23:25:54

auth.ts

Auto-generated from ./auth.ts

Authentication Module – auth.ts

File: src/auth.ts

The auth.ts module provides a minimal authentication framework that can be used as a starting point for building a real‑world authentication system.
It defines the data structures used to represent a user, exposes a small API for logging in/out and token validation, and offers two helper functions for password hashing and token generation.

⚠️ Note – The current implementation contains placeholder logic (return {} as User, return password, return 'token').
Replace these stubs with real database lookups, password hashing (e.g. bcrypt) and JWT handling before using the module in production.

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1. Overview

Feature	Description
User representation	User interface describes the shape of a user object returned by the service.
Login flow	AuthService.login() validates credentials and returns a User.
Logout	AuthService.logout() clears a user’s session.
Token validation	AuthService.validateToken() verifies a JWT and returns the associated User.
Password hashing	hashPassword() is a placeholder for a real hashing routine.
Token generation	generateToken() is a placeholder for JWT creation.

The module is intentionally lightweight so you can drop it into a project and extend it with real persistence, hashing, and token logic.

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2. Exports

Export	Type	Purpose
User	interface	Describes a user object.
LoginOptions	interface	Optional options for the login process.
AuthService	class	Core authentication service.
hashPassword	function	Helper to hash a plain‑text password.
generateToken	function	Helper to create a JWT for a user.

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3. Usage Examples

Tip: All examples assume the module is imported as import * as Auth from './auth';

3.1 Logging In

import { AuthService, LoginOptions, User } from './auth';

const auth = new AuthService();

async function signIn() {
  const options: LoginOptions = { rememberMe: true, timeout: 3600 };
  try {
    const user: User = await auth.login('alice', 's3cr3t', options);
    console.log('Logged in:', user);
  } catch (err) {
    console.error('Login failed', err);
  }
}

3.2 Logging Out

async function signOut(userId: string) {
  await auth.logout(userId);
  console.log('User logged out');
}

3.3 Validating a Token

async function checkToken(token: string) {
  try {
    const user = await auth.validateToken(token);
    console.log('Token belongs to', user.username);
  } catch (err) {
    console.error('Invalid token', err);
  }
}

3.4 Hashing a Password

import { hashPassword } from './auth';

const hashed = hashPassword('myPassword123');
console.log('Hashed password:', hashed);

3.5 Generating a Token

import { generateToken } from './auth';

const token = generateToken('user-uuid-1234');
console.log('JWT:', token);

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4. Parameters

Function / Method	Parameter	Type	Description
AuthService.login	username	string	The user’s login name.
	password	string	The user’s plain‑text password.
	options?	LoginOptions	Optional login options.
	LoginOptions.rememberMe?	boolean	Persist the session beyond the current browser session.
	LoginOptions.timeout?	number	Session timeout in seconds.
AuthService.logout	userId	string	The unique identifier of the user to log out.
AuthService.validateToken	token	string	JWT string to validate.
AuthService.validateCredentials	username	string	Username to look up.
	password	string	Password to compare.
hashPassword	password	string	Plain‑text password to hash.
generateToken	userId	string	User ID to embed in the JWT.

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5. Return Values

Function / Method	Return Type	Description
AuthService.login	Promise<User>	Resolves with the authenticated User object.
AuthService.logout	Promise<void>	Resolves when the session is cleared.
AuthService.validateToken	Promise<User>	Resolves with the User associated with the token.
AuthService.validateCredentials	Promise<User>	Resolves with the user after database lookup.
hashPassword	string	Returns the hashed password (currently the plain text).
generateToken	string	Returns a JWT string (currently a static placeholder).

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6. Extending the Module

1. Replace placeholders

   • validateCredentials → Query your user store and compare hashed passwords.
   • hashPassword → Use a library such as bcrypt or argon2.
   • generateToken → Use jsonwebtoken to sign a payload with a secret key.
   • validateToken → Verify the JWT and fetch the user from the database.

2. Add error handling
   Throw custom errors (InvalidCredentialsError, TokenExpiredError, etc.) and catch them in your application layer.

3. Persist sessions
   Store session data in a store (Redis, database, or JWT‑only).
   The rememberMe flag can control cookie expiration or token refresh logic.

4. Unit tests
   Write tests for each method, mocking the database and JWT library.

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7. Quick Reference

// Import
import { AuthService, User, LoginOptions, hashPassword, generateToken } from './auth';

// Instantiate
const auth = new AuthService();

// Login
const user: User = await auth.login('bob', 'p@ssw0rd', { rememberMe: true });

// Logout
await auth.logout(user.id);

// Validate token
const validatedUser: User = await auth.validateToken('eyJhbGciOiJI...');

// Helpers
const hashed = hashPassword('secret');
const token = generateToken(user.id);

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Happy coding! 🚀