Amazon Lambda function to post to Slack when Donald Trump tweets "Sad!" at something

sadCheck.js

'use strict';
const https = require('https');
const url = require('url');

const sadCheckVersion = '0.1.0';

/**
 * Event options:
 * twitterKey: the Twitter Application Key to be used
 * twitterSecret: the Twitter Application Secret to be used
 * slackURL: the URL for the Slack webhook
 * minutesLookback: How far back to check for a "Sad!" (Currently not implemented)
 * alwaysTrue(optional): for testing, to make sure that the bot works, always says that the last tweet is "Sad!".
 *      Will fire even if a tweet was not posted in the last minutesLookback minutes
 *
 */
const isSad = (tweetText) => tweetText.toLowerCase().includes("sad");

const encodeTwitterCredentials = (key, secret) => 
    new Buffer(
        encodeURIComponent(key) + ':' + encodeURIComponent(secret)
    ).toString('base64');

exports.handler = (event, context, callback) => {
    const twAuthReq = https.request({
            method: "POST",
            hostname: "api.twitter.com",
            path: "/oauth2/token",
            port: 443,
            headers: {
                "Authorization": "Basic " + encodeTwitterCredentials(event.twitterKey, event.twitterSecret),
                "User-Agent": "sadCheck " + sadCheckVersion,
                "Content-Type": "application/x-www-form-urlencoded;charset=UTF-8"
            }
        }, (authRes) => {
            let authJSON = '';
            authRes.on('data', (chunk) => authJSON += chunk);
            authRes.on('end', () => {  // nest other 2 calls in here- oh god damn it.
                //console.log("Authenticated to Twitter");
                //console.log(authJSON);
                const auth = JSON.parse(authJSON);
                const token = auth.access_token;
                const tweetReq = https.request({
                        method: "GET",
                        hostname: "api.twitter.com",
                        port: 443,
                        path: "/1.1/statuses/user_timeline.json?screen_name=realDonaldTrump&count=1",
                        headers: {
                            "Authorization": "Bearer " + token,
                            "User-Agent": "sadCheck " + sadCheckVersion
                        }
                    }, (tweetRes) => {
                        //console.log('Getting last tweet...');
                        let body = '';
                        tweetRes.setEncoding('utf8');
                        tweetRes.on('data', (chunk) => body += chunk);
                        tweetRes.on('end', () => {
                            //console.log('Successfully processed HTTPS response');
                            const tweets = JSON.parse(body);
                            const tweet = tweets[0];
                            if (isSad(tweet.text) || event.alwaysTrue) {
                                //console.log("Sad!");
                                const parsedURL = url.parse(event.slackURL);
                                //console.log(parsedURL.hostname + parsedURL.path);
                                const slackReq = https.request({
                                        method: "POST",
                                        port: 443,
                                        hostname: parsedURL.hostname,
                                        path: parsedURL.path
                                    }, (slackRes) => {
                                        let slackBody = '';
                                        slackRes.on('data', (chunk) => body += chunk);
                                        slackRes.on('end', () => {
                                            //console.log(slackBody);
                                            callback(null, "Sad!:" + tweet.text);});
                                    });
                                const sadAlert = `Donald Trump just called something \"Sad!\" on Twitter: <https://twitter.com/realDonaldTrump/status/${tweet.id_str}>`;
                                //console.log(sadAlert);
                                slackReq.write(JSON.stringify({text: sadAlert, unfurl_links: true}));
                                slackReq.on('error', callback);
                                slackReq.end();
                            } else {
                                callback(null, "Not Sad.");
                            }
                            //callback(null, body);
                        });
                    }
                );
                tweetReq.on('error', callback);
                tweetReq.end();
                
            })
        }
    );
    twAuthReq.write("grant_type=client_credentials");
    twAuthReq.on('error', callback);
    twAuthReq.end();
};