addfav.php

<?php
session_start();
require_once(__DIR__.'/../includes/config.include.php');
require_once(__DIR__.'/../includes/db.include.php');
require_once(__DIR__.'/../vendor/autoload.php');
require_once(__DIR__.'/../includes/autoloader.include.php');
if($_SESSION['user_data']){

    $recipe_id = (int) $_POST['recipe_id'];
    if($recipe_id) {
        $Favourties = new Favourites($Conn);
        $add = $Favourties->addToFavs($recipe_id);

        if($add) {
            echo json_encode(array(
                "success"=>true
            ));
        }

    }else{
        echo json_encode(array(
            "success"=>false,
            "reason"=>"Recipe ID not provided."
        ));
    }
}else{
    echo json_encode(array(
        "success"=>false,
        "reason"=>"User not logged in."
    ));
}