Save respondents answers only

google-sheet-webhook.gs

function saveMessage(webhookMessageResult) {
    if (webhookMessageResult.type === 'user-answers') {
        for (const question of webhookMessageResult.value.data) {
            let sheet = SpreadsheetApp.getActiveSheet();
            let lastRow = Math.max(sheet.getLastRow(), 1);

            sheet.insertRowAfter(lastRow);

            let nowDate = new Date();

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