why after saving meta value it’s saving all the values the one that i clicked?

Ok so we have things, and we want to favourite/unfavourite them as done. First, we need 2 functions:

• saeed_is_favourited( int $post_id, string $thing_to_favourite ) ( where $thing_to_favourite is the thing we’re marking as saved/favourited/etc, and $default is the value to return if we don’t know yet
• saeed_set_favourited( int $post_id, string $thing_to_favourite, bool $favourited ) where we set $thing_to_favourite on that post as favourited or not favourited

Then you will need a way to send an AJAX request to call saeed_set_favourited with the requested value.

We will store if it’s favourited in user meta using a user meta with a key like this:

saeed_favourite_123_ABC

Where 123 is the post ID, and ABC is the thing we’re favouriting/not favouriting. This thing is a string, any string of your choosing. In the examples I give, it is completely arbitrary. It is not the slug of a post or a meta key, or a username. I could use those if I wanted, or I could make them up.

---

Here is an attempt at implementing saeed_is_favourited

function saeed_is_favourited( int $post_id, string $thing_to_favourite ) : bool {
    $user_id = get_current_user_id();
    $meta_key = 'saeed_favourited_' . $post_id . '_' . $thing_to_favourite;
    $result = get_user_meta( $user_id, $meta_key, true );
    return boolval( $result );
}

Used like this:

if ( saeed_is_favourited( get_the_ID(), 'apples' ) ) {
    echo "you have favourited apples on this post";
} else {
    echo "you have not favourited apples on this post";
}

---

Here is an attempt at implementing saeed_set_favourited

function saeed_set_favourited( int $post_id, string $thing_to_favourite, bool $favourited ) : void {
    $user_id = get_current_user_id();
    $meta_key = 'saeed_favourited_' . $post_id . '_' . $thing_to_favourite;
    update_user_meta( $user_id, $meta_key, $favourited );
}

Notice that I used update_user_meta, not add_user_meta. add_user_meta can create multiple meta key/value pairs, meta keys are not unique.

---

Finally, we need a way to set if it has been favourited or not. Here is an old style Admin AJAX handler:

function saeed_ajax_favourite_a_thing() : void {
    $post_id = 0;
    if ( ! empty( $_POST['post_id'] ) {
        $post_id = intval( $_POST['post_id'] );
    } else {
        wp_die( 'a post_id number is needed, none was provided' );
    }

    $thing_to_favourite="";
    if ( ! empty( $_POST['thing_to_favourite'] ) {
        $thing_to_favourite = $_POST['thing_to_favourite'];
    } else {
        wp_die( 'a thing_to_favourite is needed, none was provided' );
    }

    $favourite = false;
    if ( ! empty( $_POST['favourite'] ) {
        $favourite = boolval( $_POST['favourite'] );
    } else {
        wp_die( 'a favourite is needed, either true or false, none was provided' );
    }
    saeed_set_favourited( $post_id, $thing_to_favourite, $favourite );
}
add_action( 'wp_ajax_saeed_ajax_favourite_a_thing', 'saeed_ajax_favourite_a_thing' );

You would then pass a post ID, a thing_to_favourite representing the thing you want to favourite, and a true/false for wether it is to be favourited or unfavourited.

E.g. this would favourite apple:

        $.ajax({
            type: 'POST',
            url: ajax_object.ajaxurl,
            data: {
                action: 'saeed_ajax_favourite_a_thing',
                post_id: post_id
                thing_to_favourite: 'apple',
                favourite: true
            }
        });

---

You should consider looking into the more modern REST API endpoints as a cleaner replacement for this AJAX handler.

You can also use saeed_is_favourited to construct your frontend, and the AJAX to toggle the items on/off.

Because it used user meta, the favouriting will work on a per user basis.

You will want to check is_user_logged_in() as this code will not work for logged out users.

Note that none of this code is tested, you may need to make modifications after integrating it into your code