index.js

function fetchData(){
    function setInterval($.ajax({
        url: "http://localhost:5000/tweets",
        success: function(data) {
            var sl = data.stop.length; //the stop array received from the server
            var gl = data.go.length;
            var cl = data.continue.length;

// //fetch function -> $.getJSON 
// //compare function -> if statment, for loop 

 var stopArray = [], 
     goArray = [],
     continueArray = []; //the arrays that we are creating and giving to the client so that the visiualations could be rendered


 function fetchData(){
     function setInterval($.ajax({
         url: "http://localhost:8000/stop",
         success: function(data) {
             var sl = data.stop.length; //the stop array received from the server
             var gl = data.go.length;
             var cl = data.continue.length;
             for(var i = 0; i < sl; i++){
                 if (stopArray[i].text === undefined) {
                     stopArray.push(data.stop[i]);
                 }
                 stopArray[i].count = data.stop[i].count;

                
             }
             for(var i = 0; i < gl; i++){
                 if (goArray[i].text === undefined) {
                     goArray.push(data.go[i]);
                 }
                 goArray[i].count = data.go[i].count;
             }
             for(var i = 0; i < cl; i++){
                 if (continueArray[i].text === undefined) {
                     continueArray.push(data.continue[i]); 
                 }
        
                continueArray[i].count = data.continue[i].count;
            }
            d3func(data);
        }
    }), 3000)
}