diagnostics.js
function modify(fn) {
  if (~modifiers.indexOf(fn)) return false;

  modifiers.push(fn);
  return true;
}
function modify(fn) {
  if (~modifiers.indexOf(fn)) return false;

  modifiers.push(fn);
  return true;
}
function modify ( fn ) { if ( ~ modifiers . indexOf ( fn ) ) return false ; modifiers . push ( fn ) ; return true ; }
Add a new message modifier to the debugger.

@param {Function} fn Modification function.
@returns {Boolean} Indication of a successful add.
@public
Add a new message modifier to the debugger .