Rate limiter pattern implementation with Node.js and Redis

rate-limiter.js

var redis     = require('redis'),
    client    = redis.createClient(),
    key       = 'counter',
    expire    = 60,
    max       = 5

client.get(key, function (err, counter) {

    if (counter !== null && counter > max) {
        console.log('Too many calls')
        client.quit()
        return
    }

    client.incr(key, function (err, counter) {
        console.log('Increment counter')
        if (counter === 1) {
            client.expire(key, expire, function (err, reply) {
                console.log('Set counter expiration')
                client.quit()
                return
            })
        }
        client.quit();
    })

})