How to get all checkout fields from WooCommerce?

I like to get all available checkout fields, including third party ones:

$fields = WC()->checkout()->checkout_fields;

returns a fatal error:

Fatal error:  Call to a member function get_country() on a non-object in
../wp-content/plugins/woocommerce/includes/class-wc-checkout.php</b> on line 768

Is there an offical way to get them?

Edit:

My plugin needs a dropdown field with all available checkout fields on the backend. What I like to have is an array like this (I var_dump the $checkout_fields variable of the WC_Checkout class) :

Array
(
    [billing] => Array
        (
            [billing_country] => Array
                (
                    [type] => country
                    [label] => Country
                    [required] => 1
                    [class] => Array
                        (
                            [0] => form-row-wide
                            [1] => address-field
                            [2] => update_totals_on_change
                        )

                )

            [billing_first_name] => Array
                (
                    [label] => First Name
                    [required] => 1
                    [class] => Array
                        (
                            [0] => form-row-first
                        )

                )

            [billing_last_name] => Array
                (
                    [label] => Last Name
                    [required] => 1
                    [class] => Array
                        (
                            [0] => form-row-last
                        )

                    [clear] => 1
                )

            [billing_company] => Array
                (
                    [label] => Company Name
                    [class] => Array
                        (
                            [0] => form-row-wide
                        )

                )

            [billing_address_1] => Array
                (
                    [label] => Address
                    [placeholder] => Street address
                    [required] => 1
                    [class] => Array
                        (
                            [0] => form-row-wide
                            [1] => address-field
                        )

                )

            [billing_address_2] => Array
                (
                    [placeholder] => Apartment, suite, unit etc. (optional)
                    [class] => Array
                        (
                            [0] => form-row-wide
                            [1] => address-field
                        )

                    [required] => 
                )

            [billing_postcode] => Array
                (
                    [label] => Postcode / Zip
                    [placeholder] => Postcode / Zip
                    [required] => 1
                    [class] => Array
                        (
                            [0] => form-row-wide
                            [1] => address-field
                        )

                    [clear] => 1
                    [validate] => Array
                        (
                            [0] => postcode
                        )

                )

            [billing_city] => Array
                (
                    [label] => Town / City
                    [placeholder] => Town / City
                    [required] => 1
                    [class] => Array
                        (
                            [0] => form-row-wide
                            [1] => address-field
                        )

                )

            [billing_state] => Array
                (
                    [type] => state
                    [label] => State / County
                    [placeholder] => State / County
                    [required] => 
                    [class] => Array
                        (
                            [0] => form-row-first
                            [1] => address-field
                        )

                    [validate] => Array
                        (
                            [0] => state
                        )

                )

            [billing_email] => Array
                (
                    [label] => Email Address
                    [required] => 1
                    [class] => Array
                        (
                            [0] => form-row-first
                        )

                    [validate] => Array
                        (
                            [0] => email
                        )

                )

            [billing_phone] => Array
                (
                    [label] => Phone
                    [required] => 1
                    [class] => Array
                        (
                            [0] => form-row-last
                        )

                    [clear] => 1
                    [validate] => Array
                        (
                            [0] => phone
                        )

                )

        )

    [shipping] => Array
        (
            [shipping_country] => Array
                (
                    [type] => country
                    [label] => Country
                    [required] => 1
                    [class] => Array
                        (
                            [0] => form-row-wide
                            [1] => address-field
                            [2] => update_totals_on_change
                        )

                )

            [shipping_first_name] => Array
                (
                    [label] => First Name
                    [required] => 1
                    [class] => Array
                        (
                            [0] => form-row-first
                        )

                )

            [shipping_last_name] => Array
                (
                    [label] => Last Name
                    [required] => 1
                    [class] => Array
                        (
                            [0] => form-row-last
                        )

                    [clear] => 1
                )

            [shipping_company] => Array
                (
                    [label] => Company Name
                    [class] => Array
                        (
                            [0] => form-row-wide
                        )

                )

            [shipping_address_1] => Array
                (
                    [label] => Address
                    [placeholder] => Street address
                    [required] => 1
                    [class] => Array
                        (
                            [0] => form-row-wide
                            [1] => address-field
                        )

                )

            [shipping_address_2] => Array
                (
                    [placeholder] => Apartment, suite, unit etc. (optional)
                    [class] => Array
                        (
                            [0] => form-row-wide
                            [1] => address-field
                        )

                    [required] => 
                )

            [shipping_postcode] => Array
                (
                    [label] => Postcode / Zip
                    [placeholder] => Postcode / Zip
                    [required] => 1
                    [class] => Array
                        (
                            [0] => form-row-wide
                            [1] => address-field
                        )

                    [clear] => 1
                    [validate] => Array
                        (
                            [0] => postcode
                        )

                )

            [shipping_city] => Array
                (
                    [label] => Town / City
                    [placeholder] => Town / City
                    [required] => 1
                    [class] => Array
                        (
                            [0] => form-row-wide
                            [1] => address-field
                        )

                )

            [shipping_state] => Array
                (
                    [type] => state
                    [label] => State / County
                    [placeholder] => State / County
                    [required] => 
                    [class] => Array
                        (
                            [0] => form-row-first
                            [1] => address-field
                        )

                    [validate] => Array
                        (
                            [0] => state
                        )

                )

        )

    [account] => Array
        (
            [account_password] => Array
                (
                    [type] => password
                    [label] => Account password
                    [required] => 1
                    [placeholder] => Password
                )

        )

    [order] => Array
        (
            [order_comments] => Array
                (
                    [type] => textarea
                    [class] => Array
                        (
                            [0] => notes
                        )

                    [label] => Order Notes
                    [placeholder] => Notes about your order, e.g. special notes for delivery.
                )

        )

)

Answer

i was facing the same issue . here’s how i managed it .

class my_checkout_fields_class {
    var $countries;

function __construct() {

        $this->countries = new WC_Countries();

}


}

Now you can get billing and shipping fields respectively in this class.

$billlingfields             = $this->countries->get_address_fields( $this->countries->get_base_country(),'billing_');

$shippingfields             = $this->countries->get_address_fields( $this->countries->get_base_country(),'shipping_');

regards