AJAX: background color change function using array values not working?

Question

I will try describe my problem as simple as possible. I have this AJAX call to GET an Json_encoded array. With the "aht_value" being retrieved I get a color background being drawn from green-ish to red-ish ( im doing a heat map). My values are being output correctly.

The problem: My "colorMe" function . I am not sure what I am doing wrong or if I am putting all my functions in the wrong place since I am doing everything inside my "success" and after my FOR loop as you see below. However, if I replace "min" for 100 and "max" for 1800 then the colors get displayed.

thanks in advance.

Array from show.php:

[{
   "username":"OXGOR",
   "aht_value":"241",
   "station":"B20"
  },
  {
   "username":"AISAI2",
    "aht_value":"199",
   "station":"B21"
  },
  {
   "username":"CAPAP3",
   "aht_value":"NA",
   "station":"B10"
  }]

map.php - JS part

<script type="text/javascript">
        $(document).ready(function() {
                $('#aht').click(function(){
                    $.ajax({
                    type:"GET",
                    url : "show_aht.php",
                    data:{ } , // do I need to pass data if im GET ting?
                    dataType: 'json',
                    success : function(data){

                        var min = data.reduce(function(prev, curr) {
                                return isNaN(curr['aht_value']) || prev < curr['aht_value'] ? prev : curr['aht_value'];
                                }, 1000000);

                                alert(min); //not returning the correct number

                                var max = data.reduce(function(prev, curr) {
                                  return isNaN(curr['aht_value']) || prev > curr['aht_value'] ? prev : curr['aht_value'];
                                }, -1000000);    

                                alert(max); //nor returning the correct number

                                //function for calculation of background color depending on aht_value               
                                function conv(x){
                                    return Math.floor((x - min) / (max - min) * 255);
                                }

                                //function for background color
                                function colorMe(v){
                                    return "rgb(" + conv(v) + "," + (255-conv(v)) + ",0)";
                                }

                        //going through all DIVs only once with this loop
                            for(var i = 0; i < data.length; i++) { // loop over results
                            var divForResult = $('#desk_' + data[i]['station']); // look for div for this object
                            if(divForResult.length) { // if a div was found
                                divForResult.html(data[i]['aht_value']).css("background-color", colorMe(data[i]['aht_value']));
                            }//end if
                            }//end for  
                    }//end success
                });//end ajax   
              });//end click
            });//end rdy
</script>

show.php: where I use json_encode

$result = array();
    foreach ($memo as $username => $memodata) {
    if (in_array($username, array_keys($user))) {
    // Match username against the keys of $user (the usernames) 
    $userdata = $user[$username];
    //if AHT is null give N/A as value
    if (is_null($memodata['aht_value'])) {
        $result[] = array( 'username'  => $userdata['username'],
                                             'aht_value' => 'NA',
                                             'station'  => $userdata['station']
                                            );
    }//end inner if 
    //else give the actual value of AHT without the decimals
    else {
        $result[] = array( 'username'  => $userdata['username'],
                           'aht_value' => substr($memodata['aht_value'],0,-3),
                           'station'   => $userdata['station']
                                            );
echo json_encode($result);

this works If I put min to 100 and max to 1800 manually in my colorMe function: what is suposd to look like

this is returning my the wrong colors as you see below whenever I use min and max calculation not giving right colors

Answer 1

You are executing map on array length, rather that on array itself. Furthermore, I would suggest you to reduce your array:

var min = data.reduce(function(prev, curr) {
  return isNaN(+curr['aht_value']) || prev < +curr['aht_value'] ? prev : +curr['aht_value'];
}, 1000000);

var max = data.reduce(function(prev, curr) {
  return isNaN(+curr['aht_value']) || prev > +curr['aht_value'] ? prev : +curr['aht_value'];
}, -1000000);   

To set the specific background whether color is NA:

function colorMe(v){
  return v == 'NA' ? "#FFF" : "rgb(" + conv(v) + "," + (255-conv(v)) + ",0)";
}

Answer 2

Your array is missing a comma after the first object.