code: function(msg, type, details) {
    if(_nodejs) {
      Error.call(this);
      Error.captureStackTrace(this, this.constructor);
    }
    this.name = type || 'jsonld.Error';
    this.message = msg || 'An unspecified JSON-LD error occurred.';
    this.details = details || {};
  }
docs: A JSON-LD Error.
  
  @param msg the error message.
  @param type the error type.
  @param details the error details.