function IdGenerator(prefix) {

  this._counter = 0;
  this._prefix = (prefix ? prefix + '-' : '') + Math.floor(Math.random() * 1000000000) + '-';
}
Util that provides unique IDs.

@class
@constructor

The ids can be customized via a given prefix and contain a random value to avoid collisions.

@param {string} [prefix] a prefix to prepend to generated ids (for better readability)