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/**
 * Hide ALL shipping options when free shipping is available and customer is NOT in certain states
 * Hide Free Shipping if customer IS in those states
 *
 * Change $excluded_states = array( 'AK','HI','GU','PR' ); to include all the states that DO NOT have free shipping
 */
add_filter( 'woocommerce_package_rates', 'hide_all_shipping_when_free_is_available' , 10, 2 );

/**
 * Hide ALL Shipping option when free shipping is available
 *
 * @param array $available_methods
 */
function hide_all_shipping_when_free_is_available( $rates, $package ) {
 
	$excluded_states = array( 'AK','HI','GU','PR' );
	if( isset( $rates['free_shipping'] ) AND !in_array( WC()->customer->shipping_state, $excluded_states ) ) :
		// Get Free Shipping array into a new array
		$freeshipping = array();
		$freeshipping = $rates['free_shipping'];
 
		// Empty the $available_methods array
		unset( $rates );
 
		// Add Free Shipping back into $avaialble_methods
		$rates = array();
		$rates[] = $freeshipping;
 
	endif;
 
	if( isset( $rates['free_shipping'] ) AND in_array( WC()->customer->shipping_state, $excluded_states ) ) {
 
		// remove free shipping option
		unset( $rates['free_shipping'] );
 
	}

	return $rates;
}