A basic AWS lamda function in nodejs to block ip address is hitting more than a limit

ipblock_awslamda.js

'use strict';

console.log('--> Loading function');

const aws = require('aws-sdk');

const s3 = new aws.S3({ apiVersion: '2006-03-01' });
const waf = new aws.WAF({ apiVersion: '2015-08-24' });

class Police {
  constructor(maxHit=100, timeGap=(6*60*60*1000)) {
    this.maxHit = maxHit;
    this.timeGap = timeGap;
    this.lastBailCheck = Date.now();
    this.hitMap = {};
  }
  static bail(ip){
    // TODO bail this ip by removing entry into waf
  }
  static jail(ip){
    // TODO jail this ip by  adding entry from waf
  }
  checkBail(){
    var nowDate = Date.now();
    if((nowDate - this.lastBailCheck) > this.timeGap){
      this.lastBailCheck = nowDate;
      this.prevMap = this.hitMap;
      this.hitMap = {};
      this.scanAndBail();
    }
  }
  scanAndBail(){
    Object.keys(this.prevMap).forEach(Police.bail);
    delete this.prevMap;
  }
  watch(ip){
    this.hitMap[ip] = (this.hitMap[ip] || 0) + 1;
    if(this.maxHit < this.hitMap[ip]){
      Police.jail(ip);
    }
    this.checkBail();
  }
}

const police = new Police();

function forOneLine(line){
  if(typeof line === 'string') {
    police.watch(line.split(' ')[3]);
  }
}

function handleResponse(data){
    data.Body.toString().split('\n').forEach(forOneLine);
}

exports.handler = (event, context, callback) => {
    //console.log('Received event:', JSON.stringify(event, null, 2));

    // Get the object from the event and show its content type
    const bucket = event.Records[0].s3.bucket.name;
    const key = decodeURIComponent(event.Records[0].s3.object.key.replace(/\+/g, ' '));
    const params = {
        Bucket: bucket,
        Key: key,
    };
    s3.getObject(params, (err, data) => {
        if (err) {
            console.log(err);
            const message = `Error getting object ${key} from bucket ${bucket}.`;
            console.log(message);
            callback(message);
        } else {
            handleResponse(data);
            callback(null, data.ContentType);
        }
    });
};