signalr.HubMessage} to a string and returns it.
   *
   * @param {HubMessage} message The message to write.
   * @returns {string} A string containing the serialized representation of the message.
   */
  writeMessage(message) {
    return TextMessageFormat.TextMessageFormat.write(JSON.stringify(message));
  }
  isInvocationMessage(message) {
    this.assertNotEmptyString(
      message.target,
      "Invalid payload for Invocation message."
    );
    if (message.invocationId !== undefined) {
      this.assertNotEmptyString(
        message.invocationId,
        "Invalid payload for Invocation message."
      );
    }
  }
  isStreamItemMessage(message) {
    this.assertNotEmptyString(
      message.invocationId,
      "Invalid payload for StreamItem message."
    );
    if (message.item === undefined) {
      throw new Error("Invalid payload for StreamItem message.");
    }
  }
  isCompletionMessage(message) {
    if (message.result && message.error) {
      throw new Error("Invalid payload for Completion message.");
    }
    if (!message.result && message.error) {
      this.assertNotEmptyString(
        message.error,
        "Invalid payload for Completion message."
      );
    }
    this.assertNotEmptyString(
      message.invocationId,
      "Invalid payload for Completion message."
    );
  }
  assertNotEmptyString(value, errorMessage) {
    if (typeof value !== "string" || value === "") {
      throw new Error(errorMessage);
    }
  }
}
exports.JsonHubProtocol = JsonHubProtocol;
PK