Dequeue/deregister Styles/JS in WordPress

/** Dequeue/deregister Styles/JS **/

function dequeue_script(){
    wp_dequeue_style( 'magnific-popup' ); //Name of Style ID wihtout css.
        wp_dequeue_script( 'jquery-magnific-popup' ); //Name of Style ID wihtout js.
}
add_action( 'wp_enqueue_scripts', 'dequeue_script', 999 );

/** Dequeue/deregister jquery-ui-datepicker **/

function dequeue_script(){
    //wp_dequeue_script( 'jquery-ui-datepicker' );
    wp_deregister_script( 'jquery-ui-datepicker' );
}
add_action( 'wp_enqueue_scripts', 'dequeue_script', 999 );