How to convert a PHP array to a specific Javascript format - php

Question

I know this must be very basic but I really don't know how to solve this. I want to turn a php array to the following notation to be used inside a javascript script. These are countries which are passed to the js script in the initialization.
Source notation (PHP)
array(3) { [0]=> array(1) { ["code"]=> string(2) "AR" } [1]=> array(1) { ["code"]=> string(2) "CO" } [2]=> array(1) { ["code"]=> string(2) "BR" } }
Desired outcome (JS)
[ "AR", "FK","CO", "BO", "BR", "CL", "CR", "EC", "GT", "HN", "LT", "MX", "PA", "PY", "PE", "ZA", "UY", "VE"]
I can reformat the origin PHP array as desired, what I need to know is how to format it to get the desired outcome.
I am using the following code to pass the array to js:
echo "<script>var codes = " . json_encode($codes) . ";</script>";

Answer 1

Looks like the following would work for you:
<?php
$arr[0]['code'] = 'AR';
$arr[1]['code'] = 'CO';
$arr[2]['code'] = 'BR';
print_r($arr);
function extract_codes($var) { return $var['code']; }
print_r(array_map('extract_codes', $arr));
echo json_encode(array_map('extract_codes', $arr));
?>
Output:
Array
(
[0] => Array
(
[code] => AR
)
[1] => Array
(
[code] => CO
)
[2] => Array
(
[code] => BR
)
)
Array
(
[0] => AR
[1] => CO
[2] => BR
)
["AR","CO","BR"]
It works by mapping each of the two-letter codes down to a normal one-dimensional array, then passing it to json_encode.

Answer 2

Going with array_reduce:
$output = array_reduce($array, function($result, $item){
$result[] = $item['code'];
return $result;
}, array());
echo json_encode($output);

Answer 3

You need to loop through your PHP associative array and set the appropriate variables.
Like this:
$item = ''; // Prevent empty variable warning
foreach ($php_array as $key => $value){
if (isset($key) && isset($value)) { // Check to see if the values are set
if ($key == "code"){ $item .= "'".$value."',"; } // Set the correct variable & structure the items
}
}
$output = substr($item,'',-1); // Remove the last character (comma)
$js_array = "[".$output."]"; // Embed the output in the js array
$code = $js_array; //The final product