JSON parse error on line 1 expecting Expecting '{', '['

Question

I've been trying to parse my data for a few days now and still have no clue how to get the results from my PHP array that is encoded by using json_encode. I am new to JQuery.

this is not working:

$.post('coordinate_array.php',{},function(data) {  //ERROR HERE EXPECTING SOMETHING??
 results = JSON.parse(data);
 for(i = 0;i < results.length;i++) {
  Paint(results[i].x, results[i].y);
 }
});

I'm getting my data from this php file:

<?php
include 'db_conn.php';

header('Content-Type: application/json'); //not sure if i need this here??

$coordinate_sql = "SELECT x_coord, y_coord FROM coordinates";
$result = mysqli_query($conn,$coordinate_sql);

//see if query is good
if($result === false) {
    die(mysqli_error()); 
}

//array that will have number of desks in map area
    while($row = mysqli_fetch_assoc($result)){  

    //get desk array count      
    $desk[] = array('x' => $row['x_coord'], 
                                    'y' => $row['y_coord']);
} //end while loop
    echo json_encode($desk); //encode the array
?>

You're not showing anything, you need to do: print(json_encode($desk));. Also, die(mysqli_error()) isn't JSON, so if something goes wrong it will be invalid JSON... You may also have an error somewhere else in your PHP file causing some notice (or whatever) being printed before the JSON. — Martin Tournoij
– Martin Tournoij, Commented Oct 1, 2014 at 14:10
And your error is? Only thing I can see is that you're not outputting your json data. json_encode() RETURNS the encoded string. it doesn't do output, so your script is effectively useless since nothing gets output to the client. You need echo json_encode($desk) — Marc B
– Marc B, Commented Oct 1, 2014 at 14:11
I added the echo and still nothing draws on screen.. this is the result I get to show you guys that my array does have values : [{"x":"20","y":"20"},{"x":"30","y":"30"},{"x":"40","y":"40"},{"x":"50","y":"50"}] ... what can I be doing wrong in the JQuery?? — mario
– mario, Commented Oct 1, 2014 at 14:33
@MarcB this is my error : Parse error on line 1: $.post('coordinate_a ^ Expecting '{', '[' — mario
– mario, Commented Oct 1, 2014 at 14:35
Why are you doing JSON.parse, data returned is an array, not a string to be parsed. — pln
– pln, Commented Oct 1, 2014 at 14:36

bfontaine · Accepted Answer · 2014-10-01 14:14:20Z

2

You’re not echoing your JSON data, so the page requested by the JS call will always be empty. Use:

echo json_encode($desk);

at the end of your file.

answered Oct 1, 2014 at 14:14

bfontaine

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1 Comment

tadman Over a year ago

@mario What is the result of this request? You should use a tool like curl to debug it, if not the Network tab in your browser.

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