I have a json column in MySQL table that contains data of this sample:

[
                        [
                            -79.4936969567481,
                            37.3504643767627
                        ],
                        [
                            -79.4936969567481,
                            37.3504643767627
                        ]
                    ]

I have a function that I would like to append ‘lat’ => and ‘lng’ => keys before the first value and second value of the array members respectively. So far I have:

$polygons = Polygon::get();

        foreach ($polygons as $polygon) {
            $coordinates = $polygon->coordinates;

            // Transform the coordinates
            $newCoordinates = array_map(function ($coordinate) {
                return [
                    'lat' => $coordinate[0],
                    'lng' => $coordinate[1],
                ];
            }, $coordinates);

            // Update the model's coordinates column
            $polygon->coordinates = $newCoordinates;
            $polygon->save();
        }

However, its resulting in

[
    {
        "lat": -79.4936969567481,
        "lng": 37.3504643767627
    },
    {
        "lat": -79.4936789563065,
        "lng": 37.3504513771715
    }
]

What could I be doing wrong? The { should be replaced by [, } by ] and : by =>