function(control, newName) {
    var oldName = control.$name;

    if (this[oldName] === control) {
      delete this[oldName];
    }
    this[newName] = control;
    control.$name = newName;
  }
function(control, newName) {
    var oldName = control.$name;

    if (this[oldName] === control) {
      delete this[oldName];
    }
    this[newName] = control;
    control.$name = newName;
  }
function ( control , newName ) { var oldName = control . $name ; if ( this [ oldName ] === control ) { delete this [ oldName ] ; } this [ newName ] = control ; control . $name = newName ; }
Private API: rename a form control
Private API : rename a form control