Printing JavaScript Objects from Associatve Array

Question

What if I want to console.log only one 1(ANY) javaScript object. Currenly it displays all 1000. Please Look at Php and JS files:

Server.php

if ($conn->connect_error) {
die("Connection failed: " . $conn->connect_error);
}
$data = array("coordinates" => array());

$sql = "SELECT Lng, Lat, URL FROM results LIMIT 1000";
$result = $conn->query($sql);
if ($result->num_rows > 0) {
    while($row = $result->fetch_assoc()) {
        $data["coordinates"][] = $row;
    }
}
echo json_encode($data);

Index.js

{
$.ajax({
  dataType: "json",
  url: 'server.php',
  //data: [],
  data: {param: ""},
  success: function(data)
  {
    //JSON.parse(data);  
    console.log(data);
  addMarkers(data,map);
  }
});

}

Answer 1

It's displaying all because you're logging all. You're returning 1000 objects from your db call, which is why it's logging all.

You could find a single object by a key using something like:

data.filter(x => x.myPropValue == "myString");

And log that.

Answer 2

If you want your JavaScript AJAX call to not log all 1000 items, you might want to change your php code ( $sql = "SELECT Lng, Lat, URL FROM results LIMIT 1000"; ) to only send one item per call (eg replace 1000 with 1), and then adjust the Server Logic to get the respective next item on a following AJAX call.

This would also make your Server & Client faster, since it's reducing the total data amount, but would still allow 1000 or more items.

You could also try and add a parameter, so that you can tell your php code how many items your JS code needs to get.

Answer 3

It helps to understand the json data structure you are outputting, and how you access certain elements from an object made by that json. In your case, you end up with a single object named data (as defined by the .ajax success callback). That object then contains just one keyname with an array of objects. The keyname is coordinates . Inside each array value, is an object from your database row return.

If you simply wish to show one object from your array of objects, this is all you need:

console.log( data.coordinates[0] );

That would show the first object in the array (arrays start with [0]).

console.log( data.coordinates[999] );

That would show the last object in the array of 1000.

console.log( data.coordinates[ data.coordinates.length-1 ] );

That would show the last object in an array of a variable size, using itself as the determiner.