backlog pending users to slack

function myFunction() {
  const users = getUsers();
  const pendingUsers = filterPendingUsers(users);
  const attachments = createAttachments(pendingUsers);
  postSlackAttachments(attachments);
}

function getUsers() {
  const url = PropertiesService.getScriptProperties().getProperty('BACKLOG_URL') + "/api/v2/users?apiKey=" + PropertiesService.getScriptProperties().getProperty('BACKLOG_API_TOKEN');
  
  var options = {
    "method": "get",
    "contentType": "application/json"
  };

  const response = UrlFetchApp.fetch(url, options);
  return JSON.parse(response.getContentText());
}

function filterPendingUsers(users) {
  return users.filter(a => a.lang == null); // 招待完了していないユーザーはlang nullのため判定に利用する
}

function createAttachments(pendingUsers) {
  return pendingUsers.map(user => {
    return {
      "color": "good",
      "fields": [{
          "title": "email",
          "value": user.mailAddress,
          "short": false
        }]
    };
  });
}

function postSlackAttachments(attachments) {
  const slackUrl = PropertiesService.getScriptProperties().getProperty('SLACK_WEBHOOK');

  const webhookUrl = slackUrl;
  for (var i = 0; i < attachments.length; i++) {
    if (0 < i) {
      Utilities.sleep(1000);
    }
    var attachment = attachments[i];
    var username = "backlog bot";

    var msgJson = {
      "username": username,
      "attachments": [attachment]
    };
    var payload = JSON.stringify(msgJson);

    var options = {
      "method": "post",
      "contentType": "application/json",
      "payload": payload
    };

    UrlFetchApp.fetch(webhookUrl, options);
  }
}