joyful2.js

app.get('/tweets',
	require('connect-ensure-login').ensureLoggedIn(),
	function(req, res) {

	    // Create client instance to connect to Twitter
	    // We pass in the access token we got from the OAuth process
	    var T = new Twit({
		consumer_key: process.env['TWITTER_CONSUMER_KEY'],
		consumer_secret: process.env['TWITTER_CONSUMER_SECRET'],
		access_token: req.user.token,
		access_token_secret: req.user.tokenSecret,
		timeout_ms:           60*1000,  // optional HTTP request timeout to apply to all requests.
		strictSSL:            true,     // optional - requires SSL certificates to be valid.
	    })

	    // Fetch the tweets from the user's timeline, we need the
	    // 'extended' mode to get the full 240 characters
	    T.get('statuses/home_timeline', { count: 20,
					      tweet_mode: 'extended' },
		  async (err, data, response) => {

		      // Create an agent instance that we will use to connect
		      // to the Watson Tone Analyzer service, we include a throttle
		      // adapter to attempt to prevent us overloading the API rate limits
		      const agent = axios.create({
			  timeout: 1000,
			  auth: {username: 'apikey',
				 password: tone_key},
			  adapter: throttleAdapterEnhancer(axios.defaults.adapter, { threshold: 1000 })
		      });

		      // Process all the tweets in parallel async
		      let tweets = await Promise.all(data.map(async tweet => {
			  // if the tweet is a retweet then the actual text is in the 
			  // retweeted status
			  let status = tweet.retweeted_status || tweet;
			  let text = status.full_text;

			  // connect to tone analyser and send the text to it
			  // insert the returned document tones into the original
			  // tweet object
			  try {
			      let tones = await agent.post(tone_url, {text: text});
			      tweet.tones = tones.data.document_tone.tones;
			  } catch (error) {
			      console.error(error);
			  }
			  return tweet;
		      }))
		      
		      // Filter through all the tweets we now have
		      let joy_tweets = tweets.filter(tweet => {
			  // ensure we have actually got tones for the tweet
			  if (tweet.tones) {
			      // loop through each tone and if it is angry or protected
		              // then filter this tweet out
			      for (let i=0; i<tweet.tones.length; i++) {
				  if(tweet.tones[i].tone_id == 'anger') {
				      return false;
				  }
				  if(tweet.user.protected) {
				      return false;
				  }
				  
			      }
			      // if the tweet is joyful then include it
			      for (let i=0; i<tweet.tones.length; i++) {
				  if(tweet.tones[i].tone_id == 'joy') {
				      return true;
				  }
			      }
			  }
		      })
		      
		      res.json({'tweets': joy_tweets});
		  })

	});