google-sheet-webhook (grouped by answers of first single-choice survey question).gs

function saveMessage(webhookMessageResult) {
    if (webhookMessageResult.type === 'user-answers') {
        const dialogs = webhookMessageResult.value.data;

        let sheets = SpreadsheetApp.getActiveSpreadsheet().getSheets();
        let sheet = sheets[0];

        for (let i = 0; i < dialogs.length; i++) {
            const dialog = dialogs[i];

            if (i === 0 && dialog.type === 'survey') {
              let activeSpreadsheet = SpreadsheetApp.getActiveSpreadsheet();
              let newSheet = activeSpreadsheet.getSheetByName(dialog.answer);

              if (newSheet == null) {
                newSheet = activeSpreadsheet.insertSheet();
                newSheet.setName(dialog.answer);
              }

              sheet = SpreadsheetApp.getActiveSpreadsheet().getSheetByName(dialog.answer);

              continue;
            }

            let lastRow = Math.max(sheet.getLastRow(), 1);
            let nowDate = new Date();

            sheet.insertRowAfter(lastRow);

            sheet.getRange(lastRow + 1, 1).setValue(nowDate);
            sheet.getRange(lastRow + 1, 2).setValue(webhookMessageResult.value.userName);
            sheet.getRange(lastRow + 1, 3).setValue(dialog.question);
            sheet.getRange(lastRow + 1, 4).setValue(dialog.answer);

            SpreadsheetApp.flush();
        }
    }
}

//this is a function that fires when the webapp receives a GET request
function doGet(e) {
    return HtmlService.createHtmlOutput("request received");
}

//this is a function that fires when the webapp receives a POST request
function doPost(data) {
    if (
        data &&
        data.postData &&
        data.postData.contents
    ) {
        let webhookMessage = JSON.stringify(data.postData.contents);

        while (typeof webhookMessage === 'string') {
            webhookMessage = JSON.parse(webhookMessage);
        }

        if (Array.isArray(webhookMessage.result)) {
            for (const result of webhookMessage.result) {
                saveMessage(result);
            }
        } else {
            saveMessage(webhookMessage.result);
        }
    }

    return HtmlService.createHtmlOutput("post request received");
}