Add US Territories to the list of US States in Gravity Forms

add-territories-to-gravity-forms.php

<?php

/**
 * Add US Territories to the list of US States in Gravity Forms.
 *
 * @param array $states The default list of states.
 * @return array
 */
function filter_us_states( $states ) {
	// Add American Samoa.
	$previous_key = array_search( 'Alaska', $states, true );
	$states = array_insert_after( $states, $previous_key, array( 'American Samoa' ) );

	// Add Guam.
	$previous_key = array_search( 'Georgia', $states, true );
	$states = array_insert_after( $states, $previous_key, array( 'Guam' ) );
	
	// Add Northern Mariana Islands.
	$previous_key = array_search( 'North Dakota', $states, true );
	$states = array_insert_after( $states, $previous_key, array( 'Northern Mariana Islands' ) );
	
	// Add Puerto Rico.
	$previous_key = array_search( 'Pennsylvania', $states, true );
	$states = array_insert_after( $states, $previous_key, array( 'Puerto Rico' ) );
	
	// Add U.S. Virgin Islands.
	$previous_key = array_search( 'Texas', $states, true );
	$states = array_insert_after( $states, $previous_key, array( 'U.S. Virgin Islands' ) );

	return $states;
}
add_filter( 'gform_us_states', 'filter_us_states' );

/**
 * Insert a value or key/value pair after a specific key in an array.  If key doesn't exist, value is appended
 * to the end of the array.
 *
 * @see https://gist.github.com/wpscholar/0deadce1bbfa4adb4e4c
 *
 * @param array $array
 * @param string $key
 * @param array $new
 *
 * @return array
 */
function array_insert_after( array $array, $key, array $new ) {
	$keys = array_keys( $array );
	$index = array_search( $key, $keys );
	$pos = false === $index ? count( $array ) : $index + 1;

	return array_merge( array_slice( $array, 0, $pos ), $new, array_slice( $array, $pos ) );
}