arrayToCssClasses.php

/**
 * Conditionally compiles an array of classes and contrainnts into a CSS class string
 *
 * The array key contains the classes you wish to add
 * The value is a boolean expression
 *
 * If the array element has a numeric key, it will always be included
 */

function arrayToCssClasses($inArrClasses)
{
  if ( is_null($inArrClasses) ) {
    return [];
  }
  
  // If the given value is not an array and not null, wrap it in one.
  $arrClassList = is_array($inArrClasses) ? $inArrClasses : [$inArrClasses];

  $arrClasses = [];

  foreach ($arrClassList as $class => $constraint) {
      if ( is_numeric($class) ) {
          $arrClasses[] = $constraint;
      } elseif ($constraint) {
          $arrClasses[] = $class;
      }
  }

  return implode(' ', $arrClasses);
}