WooCommerce Change Add to Cart Button Text On Single Product Page

/**
* @Title: WooCommerce Change Add to Cart Button Text for particular product type on Single Product Page
* @Author: Mina Pansuriya
* @Website: http://minapansuriya.com
*/
add_filter( 'woocommerce_product_single_add_to_cart_text', 'pbs_change_single_product_add_to_cart_text', 2, 99 ); 
 
function pbs_change_single_product_add_to_cart_text($dflt_add_to_cart_text, $product) {
 
    $product_type = $product->product_type;
   
    // Get the product type
    switch ( $product_type ) {
        case 'external':
            return __( 'Buy on Amazon', 'woocommerce' );
            
        case 'grouped':
            return __( 'Buy Now', 'woocommerce' );
        
        case 'simple': // Simple, Virtual, Downloadable Product
            return __( 'Buy Now', 'woocommerce' );
        
        case 'variable':
            return __( 'Buy Now', 'woocommerce' );
    
    }
    return $dflt_add_to_cart_text;
 
}