public static function enqueue_admin_js() {
		wc_enqueue_js(
			"jQuery( function( $ ) {
				function wcFreeShippingShowHideMinAmountField( el ) {
					var form = $( el ).closest( 'form' );
					var minAmountField = $( '#woocommerce_free_shipping_min_amount', form ).closest( 'tr' );
					var ignoreDiscountField = $( '#woocommerce_free_shipping_ignore_discounts', form ).closest( 'tr' );
					if ( 'coupon' === $( el ).val() || '' === $( el ).val() ) {
						minAmountField.hide();
						ignoreDiscountField.hide();
					} else {
						minAmountField.show();
						ignoreDiscountField.show();
					}
				}

				$( document.body ).on( 'change', '#woocommerce_free_shipping_requires', function() {
					wcFreeShippingShowHideMinAmountField( this );
				});

				// Change while load.
				$( '#woocommerce_free_shipping_requires' ).change();
				$( document.body ).on( 'wc_backbone_modal_loaded', function( evt, target ) {
					if ( 'wc-modal-shipping-method-settings' === target ) {
						wcFreeShippingShowHideMinAmountField( $( '#wc-backbone-modal-dialog #woocommerce_free_shipping_requires', evt.currentTarget ) );
					}
				} );
			});"
		);
	}