Converting a string (e.g. 'yes' or 'no') to a boolean

string-to-bool.php

<?php
/**
 * Converts a string (e.g. 'yes' or 'no') to a bool.
 *
 * @since   1.0.0
 * @param   string $input   String to convert.
 * @return  bool
 */
function prefix_string_to_bool( $input ) {
	return is_bool( $input ) ? $input : ( 'yes' === $input || 1 === $input || 'true' === $input || 'TRUE' === $input || '1' === $input );
}