how to combine all data in 1 column

[nagastar]

I want to combine the data in column B in google sheets. after that, all the data will be sent to the chatwork chat application with one chat notification only.
this is my code:

 function sendAllRowsToChatworkExceptLastRow() {

  const spreadsheet = SpreadsheetApp.getActiveSpreadsheet();

  const sheet = spreadsheet.getSheetByName('GAS');

  const lastRow = sheet.getLastRow();

  const lastColumn = sheet.getLastColumn();

  for (let i = lastRow; i > 1; i--) {

    const rowValues = sheet.getRange(i, 1, 1, lastColumn).getValues()[0];

    // Create a message to send to ChatWork.

    const message = `[info][title]this is task today; [/title]

      ${rowValues.join(", ")}

      [/info]`;

    // Send the message to ChatWork.

    const client = ChatWorkClient.factory({token: "0c0219265533e71d160bda27ec3f"});

    client.sendMessage({room_id: "room_Id", body: message});

  }

}

Currently, I have created the code but the problem now is that if there are 3 rows of data in column B, it will send a message 3 times to chatwork consecutively.
like this picture from the chatwork chat application:

 i want if there is data in column B for 3 rows then it will combine the data in the 3 rows of column B and send it to the chatwork application in just one message.
This is roughly the expected result:

this is task today :

cleaning room,

cleaning toilets,

cleaning garden

[Jiří Janda]

Try this:

function sendAllRowsToChatworkExceptLastRow() {
  const spreadsheet = SpreadsheetApp.getActiveSpreadsheet();
  const sheet = spreadsheet.getSheetByName('GAS');

  const lastRow = sheet.getLastRow();
  const lastColumn = sheet.getLastColumn();

  let combinedMessage = ''; // Initialize an empty string to store the combined message.

  for (let i = lastRow; i > 1; i--) {

    const rowValues = sheet.getRange(i, 2).getValue(); // Get the value from column B (index 2).

    // Append the current row value to the combined message.
    combinedMessage += rowValues + "\n";
  }

  // Create a message to send to ChatWork with the combined data from column B.

  const message = `[info][title]this is task today; [/title]

      ${combinedMessage}

      [/info]`;

  // Send the message to ChatWork.
  const client = ChatWorkClient.factory({token: "0c0219265533e71d160bda27ec3f"});
  client.sendMessage({room_id: "room_Id", body: message});
}