lib/box-shadow.js
function flipShadow(value) {
  var elements = value.split(/\s+/);

  if (!elements) { return value; }

  var inset = (elements[0] == 'inset') ? elements.shift() + ' ' : '';
  var property = elements[0].match(/^([-+]?\d+)(\w*)$/);

  if (!property) { return value; }

  return inset + [(-1 * +property[1]) + property[2]]
      .concat(elements.splice(1)).join(' ');
}
function flipShadow(value) {
  var elements = value.split(/\s+/);

  if (!elements) { return value; }

  var inset = (elements[0] == 'inset') ? elements.shift() + ' ' : '';
  var property = elements[0].match(/^([-+]?\d+)(\w*)$/);

  if (!property) { return value; }

  return inset + [(-1 * +property[1]) + property[2]]
      .concat(elements.splice(1)).join(' ');
}
function flipShadow ( value ) { var elements = value . split ( / \s+ / ) ; if ( ! elements ) { return value ; } var inset = ( elements [ 0 ] == 'inset' ) ? elements . shift ( ) + ' ' : '' ; var property = elements [ 0 ] . match ( / ^([-+]?\d+)(\w*)$ / ) ; if ( ! property ) { return value ; } return inset + [ ( - 1 * + property [ 1 ] ) + property [ 2 ] ] . concat ( elements . splice ( 1 ) ) . join ( ' ' ) ; }
Flip a single `box-shadow` value.

@param {String} value Value
@return {String}
Flip a single box - shadow value .