program.js

const request = require('request');

var urls = { deals: 'https://api.pipedrive.com/v1/deals?start=0&api_token=12345',
             activities : 'https://api.pipedrive.com/v1/activities?start=0&api_token=12345' };

var applications = [];
var alreadyHave4506T = [];

function getIt (url, callback) {
    request(url, function (error, response, body) {
        if (error) {
            return console.log(error);
        }    
        var parse = JSON.parse(body).data;
        callback(parse);
    });
}

function inStageTwo (deal) {
    if (deal.stage_id === 2) {
        applications.push(deal.id);
    }
}

function has4506T (activity) {
    if (activity.subject === '4506-T') {
        alreadyHave4506T.push(activity.deal_id);  
    }
}

getIt (urls.deals, function (deals) {
    deals.forEach(inStageTwo);
    console.log (applications);
});

getIt (urls.activities, function (activities) {
    activities.forEach(has4506T);
    console.log(alreadyHave4506T);
});