Preventing Brute Force Using Node and Express JS

rate-limiter-flexible package with Redis or Mongo for distributed apps and in-Memory or with Cluster helps

Here is example with Redis

const { RateLimiterRedis } = require('rate-limiter-flexible');
const Redis = require('ioredis');

const redisClient = new Redis({
  options: {
    enableOfflineQueue: false
  }
});

const opts = {
  redis: redisClient,
  points: 5, // 5 points
  duration: 15 * 60, // Per 15 minutes
  blockDuration: 15 * 60, // block for 15 minutes if more than points consumed 
};

const rateLimiter = new RateLimiterRedis(opts);

app.post('/auth', (req, res, next) => {
  // Consume 1 point for each login attempt
  rateLimiter.consume(req.connection.remoteAddress)
    .then((data) => {
      const loggedIn = loginUser();
      if (!loggedIn) {
        // Message to user
        res.status(400).send(data.remainingPoints + ' attempts left');
      } else {
        // successful login
      }
    })
    .catch((rejRes) => {
      // Blocked
      const secBeforeNext = Math.ceil(rejRes.msBeforeNext / 1000) || 1;
      res.set('Retry-After', String(secBeforeNext));
      res.status(429).send('Too Many Requests');
    });
});

Maybe something like this might help you get started.

var failures = {};

function tryToLogin() {
    var f = failures[remoteIp];
    if (f && Date.now() < f.nextTry) {
        // Throttled. Can't try yet.
        return res.error();
    }

    // Otherwise do login
    ...
}

function onLoginFail() {
    var f = failures[remoteIp] = failures[remoteIp] || {count: 0, nextTry: new Date()};
    ++f.count;
    f.nextTry.setTime(Date.now() + 2000 * f.count); // Wait another two seconds for every failed attempt
}

function onLoginSuccess() { delete failures[remoteIp]; }

// Clean up people that have given up
var MINS10 = 600000, MINS30 = 3 * MINS10;
setInterval(function() {
    for (var ip in failures) {
        if (Date.now() - failures[ip].nextTry > MINS10) {
            delete failures[ip];
        }
    }
}, MINS30);

So after doing some searching, I wasn't able to find a solution I liked so I wrote my own based on Trevor's solution and express-brute. You can find it here.