PHP json_encode to JS Array of Objects

Question

I'm trying to figure out how to translate a PHP array to json, to a javascript array of objects:

$latlng = array();
    $properties = get_posts(array(
        'posts_per_page' => -1,
        'post_type' => array('house', 'townhouse', 'condo'),
        'status' => 'publish'
    ));
    foreach ($properties as $prop) {
        $lat = get_field('latitude', $prop, false);
        $lng = get_field('longitude', $prop, false);
        array_push($latlng, array($lat, $lng));
    }

    echo json_encode($latlng);
    wp_die();

But I need the final JS array to look like this:

locations = [
                    {lat: -31.563910, lng: 147.154312},
                    {lat: -33.718234, lng: 150.363181},
                    {lat: -33.727111, lng: 150.371124},
                    {lat: -33.848588, lng: 151.209834},
                    {lat: -33.851702, lng: 151.216968},
                    {lat: -34.671264, lng: 150.863657},
                    {lat: -35.304724, lng: 148.662905},
                    {lat: -36.817685, lng: 175.699196},
                    {lat: -36.828611, lng: 175.790222},
                    {lat: -37.750000, lng: 145.116667},
                    {lat: -37.759859, lng: 145.128708},
                    {lat: -37.765015, lng: 145.133858},
                    {lat: -37.770104, lng: 145.143299},
                    {lat: -37.773700, lng: 145.145187},
                    {lat: -37.774785, lng: 145.137978},
                    {lat: -37.819616, lng: 144.968119},
                    {lat: -38.330766, lng: 144.695692},
                    {lat: -39.927193, lng: 175.053218},
                    {lat: -41.330162, lng: 174.865694},
                    {lat: -42.734358, lng: 147.439506},
                    {lat: -42.734358, lng: 147.501315},
                    {lat: -42.735258, lng: 147.438000},
                    {lat: -43.999792, lng: 170.463352}
                ]

This is so I can use locations.map(function(location, i) { to iterate over the bounds.

Answer 1

Your $latlng is an array of arrays, and you want your JSON to be an array of objects, with lat and lng fields. So you need to do:

$latlng = array();
$properties = get_posts(array(
    'posts_per_page' => -1,
    'post_type' => array('house', 'townhouse', 'condo'),
    'status' => 'publish'
));
foreach ($properties as $prop) {
    $lat = get_field('latitude', $prop, false);
    $lng = get_field('longitude', $prop, false);
    array_push($latlng, array('lat' => $lat, 'lng' => $lng));
}

echo json_encode($latlng, JSON_NUMERIC_CHECK /* PHP >= 5.3.3 */);
wp_die();

We just pushed an object instead of an array containing the values:

array_push($latlng, array('lat' => $lat, 'lng' => $lng));

Hope it helps.