salting-and-hashing.ts

import { randomBytes, scryptSync, timingSafeEqual } from "node:crypto";

type User = { email: string; password: string };
const users: User[] = [];

function signup(email: string, password: string) {
  const salt = randomBytes(16).toString("hex");
  const hashedPassword = scryptSync(password, salt, 64).toString("hex");

  const user = { email, password: `${salt}:${hashedPassword}` };
  users.push(user);

  return user;
}

function login(email: string, password: string) {
  const user = users.find(v => v.email === email)!;

  const [salt, key] = user.password.split(":");
  const hashedBuffer = scryptSync(password, salt, 64);

  const keyBuffer = Buffer.from(key, "hex");
  const match = timingSafeEqual(hashedBuffer, keyBuffer);

  if (match) return "login success";
  return "login fail";
}

const user = signup("a@b.com", "abc1234");
console.log({ user });
const wrongCreds = login("a@b.com", "abc123");
console.log({ wrongCreds });
const rightCreds = login("a@b.com", "abc1234");
console.log({ rightCreds });