PHP, WordPress, Prepend a namespace in WordPress body_class() function, so that it won't clash with other class names. E.g. `root--`.

body_class_prefix.php

/**
 * Prepend a namespace in WordPress body_class() function
 * @param  string $prefix  The desired prefix
 * @param  string $classes Additional classes separated by single space
 * @return string          Single space separated list of classes
 */
function body_class_prefix($prefix, $classes = '')
{
    global $wp_query;
    $output = '';
    $body_classes = get_body_class();
    foreach ($body_classes as $class) {
        $output .= $prefix.$class . ' ';
    }
    echo "class='$output$classes' ";
}

Thanks for the code! I made it into a filter:

function prepend_body_class( $classes ) {
  $prepended_classes = array_map(
    function($value) {
      return 'body-' . $value;
    },
    $classes
  );
  return $prepended_classes;
}
add_filter( 'body_class', 'prepend_body_class' );