Overriding parent theme javascript from child theme

Question

My parent theme has a script in \includes\js\custom.js, and I am trying to override this from my child theme. I can see from my parent theme that it is en-queued using this code: (I've trimmed some non-relevant lines of wp_enqueue_script() calls.)

function my_deregister_scripts() {
        wp_deregister_script( 'jquery' );
        wp_enqueue_script('jquery', get_template_directory_uri().'/includes/js/jquery.min.js', false, '1.6.4');
        wp_enqueue_script('jquery-custom', get_template_directory_uri().'/includes/js/custom.js', false, '1.0');
        if ( is_singular() && get_option('thread_comments') ) wp_enqueue_script( 'comment-reply' );
}

At first , I thought I could simply add some code into my own child functions.php like this:

function custom_script_fix()
{
    wp_dequeue_script( 'jquery-custom' );
    wp_enqueue_script( 'child-jquery-custom', get_stylesheet_directory_uri() .'/includes/js/custom.js', false, '1.0');
}
add_action( 'wp_enqueue_scripts', 'custom_script_fix' );

but then I read in the codex that nowadays, the child functions.php is run immediately before the parent functions.php. This means that I am dequeueing something that will obly be enqueued again in the parent functions.php. This results in my script being loaded first, followed by the parent script:

So, how would I do this without modifying the parent theme in any way?

Answer 1

By simply registering the script and using the same handle that is being used in the parent theme, it takes precedence. Thus when the parent theme gets around to enqueueing its own version, the handle is already allocated, and it enqueues the override instead.

function custom_script_fix()
{
    // use same handle as parent theme to override ('jquery-custom')
    wp_register_script('jquery-custom', get_stylesheet_directory_uri() .'/includes/js/custom.js', false, '1.0');
}

add_action( 'wp_enqueue_scripts', 'custom_script_fix' );

The description on wp_enqueue_script() specifies it won't replace the registered version. You may need to set a lower $priority on add_action() to ensure your override script is registered first.