$myFile = "json/posts.json";
$arr_data = array(); // create empty array

try
{
    //Get form data
    $formdata = array(
        'title'=> strip_tags($name,"<h1> <h2> <h3> <h4>"),
        'url'=> "/content/$name4.html",
        'category'=> 1,
        "date" => date("Y-M-D")
    );

    //Get data from existing json file
    $jsondata = file_get_contents($myFile);

    // converts json data into array
    $arr_data = json_decode($jsondata, true);

    // Push user data to array
    array_push($arr_data,$formdata);

    //Convert updated array to JSON
    $jsondata = json_encode($arr_data, JSON_PRETTY_PRINT);

    //write json data into data.json file
    if(file_put_contents($myFile, $jsondata)) {
        echo 'Data successfully saved';
    }
    else 
        echo "error";

}
catch (Exception $e) {
    echo 'Caught exception: ',  $e->getMessage(), "\n";
}

fclose($fp);