index.js

require('dotenv').config()
var https = require('https');
var slack = require('slack-incoming-webhook');
var send = slack({
  url: process.env.SLACK_WEBHOOK_URL,
});
var moment = require('moment');
var now = moment();

var timeOff;
var people;
var message = '';

function isAWeekDay(callback) {
  var weekday = moment().isoWeekday();
  if(weekday < 6) {
    callback();
  }
  else {
    console.log('It\'s the weekend!');
  }
}

function getTimeOff(callback) {
  var options = {
    host: 'api.float.com',
    port: 443,
    path: '/v3/timeoffs?sort=-start_date',
    headers: {
      'Authorization' : 'Bearer ' + process.env.FLOAT_ACCESS_TOKEN
    }
  };
  return https.get(options, function(response) {
      // Continuously update stream with data
      var body = '';
      response.on('data', function(d) {
          body += d;
      });
      response.on('end', function() {
          // Data reception is done, do whatever with it!
          timeOff = JSON.parse(body);
          callback();
      });
  }).on('error', (e) => {
    console.error(e);
  });;
}

function filterTimeOff(callback) {
  timeOff.forEach( function(element, index) {
    var inRange = false;
    var startDate = element.start_date;
    var endDate = element.end_date;
    // if today is before end date and after start date
    if((moment(now).isSameOrBefore(endDate, 'day'))
      &&
      (moment(now).isSameOrAfter(startDate, 'day'))) {
      inRange = true;
      console.log('Start Date: ' + startDate);
      console.log('End Date: ' + endDate);
    }
    element.in_range = inRange;
  });
  callback();
}

function getPeople(callback) {
  var options = {
    host: 'api.float.com',
    port: 443,
    path: '/v3/people',
      headers: {
        'Authorization' : 'Bearer ' + process.env.FLOAT_ACCESS_TOKEN
      }
    };
    https.get(options, function(response) {
        // Continuously update stream with data
        var body = '';
        response.on('data', function(d) {
          body += d;
        });
        response.on('end', function() {
          // Data reception is done, do whatever with it!
          people = JSON.parse(body);
          callback();
        });
    }).on('error', (e) => {
      console.error(e);
    });
}

function addPeopleToTimeOff(callback) {
  var counter = 0;
  timeOff.forEach( function(element, index) {
    var id = element.people_ids[0];
     element.person = people.find(person => {
      return person.people_id === id;
    })
    timeOff[index] = element;
    counter++;

    if(counter === timeOff.length) {
      callback();
    }
  });
}

function compileSlackMessage(callback) {
  var count = 0;
  timeOff.forEach( function(element, index) {
    if(element.in_range) {
      count++;
    }
  });
  if (count > 1) {
    message += 'There are ' + count + ' people off work today\n';
  }
  else if (count > 0) {
    message += 'There is ' + count + ' person off work today\n';
  }
  message += generatePersonList();
  callback();
}

function generatePersonList() {
  var message = '';
  timeOff.forEach( function(element, index) {
    if(element.in_range) {
      personName = element.person.name;
      message += '*' + personName +'*';
      if(element.timeoff_notes !== '') {
        message += ' ' + element.timeoff_notes;
      }
      else {
        message += ' ' + element.timeoff_type_name;
      }
      if(!element.full_day) {
        message += ' (' + element.hours + ' hours)';
      }
      message += '\n';
    }
  });
  return message;
}

function postToSlack(callback) {
  if (message == '') {
    console.log('Nothing to post');
    callback();
    return;
  }
  else {
    send(message);
    callback();
  }
}

function init() {
  isAWeekDay(function() {
    getTimeOff(function() {
      filterTimeOff(function() {
        getPeople(function() {
          addPeopleToTimeOff(function() {
            compileSlackMessage(function() {
              postToSlack(function() {
                console.log('Done!');
              })
            })
          });
        })
      });
    });
  })
};

init();