This script acts as Slack Bot to post one tip once a day to a defined channel.

.A.README.md

Tip Of The Day Bot

This script acts as Slack Bot to post one tip once a day to a defined channel.

.clasp.json

{
  "scriptId":"",
  "fileExtension": "ts"
}

appscript.json

{
  "timeZone": "Europe/Berlin",
  "dependencies": {
  },
  "exceptionLogging": "STACKDRIVER",
  "urlFetchWhitelist": [
    "https://hooks.slack.com/XXX/XXX"
  ]
}

main.ts

function setup() {
  createTrigger();
}

function main() {
  tipOfTheDay(getProperty('SPREADSHEET_ID_1'), getProperty('CHANNEL_NAME_1'));
  tipOfTheDay(getProperty('SPREADSHEET_ID_2'), getProperty('CHANNEL_NAME_2'));
}

function getProperty(key: string) {
  const scriptProperties: GoogleAppsScript.Properties.Properties = PropertiesService.getScriptProperties();
  return scriptProperties.getProperty(key);
}

function tipOfTheDay(fileId: string, channel: string) {
  const activeRange: GoogleAppsScript.Spreadsheet.Range = openAndActivateSpreadsheet(fileId);
  const tips: string[] = getTips(activeRange);
  const tipOfTheDay: string = getMessage(tips);
  postMsgToSlack(tipOfTheDay, channel);
}

function openAndActivateSpreadsheet(fileId): GoogleAppsScript.Spreadsheet.Range {
  const spreadsheet = SpreadsheetApp.openById(fileId);
  const firstSheet = spreadsheet.getSheets()[0];
  return spreadsheet.setActiveSheet(firstSheet).getRange('A2:A100').activate();
}

function getTips(range: GoogleAppsScript.Spreadsheet.Range) {
  const numRows = range.getNumRows();
  let row = [];
  for (let i = 1; i <= numRows; i++) {
    let currentValue = range.getCell(i,1).getValue();
    if (!currentValue.length) {
      break;
    }
    row.push(currentValue)
  }
  return row;
}

function getMessage(messages) {
  return messages[Math.floor(Math.random() * messages.length)];
}

function postMsgToSlack(message: string, channel: string) {
  const formData = {
    payload: `{"channel": "${channel}", "username": "TipOfTheDayBot", "text": "${message}", "icon_emoji": ":hoff:", "mrkdwn": true}`
  };
  let options = {
    'method' : 'post',
    'payload' : formData
  };
  UrlFetchApp.fetch(getProperty('SLACK_WEBHOOK_URL'), options);
}

function createTrigger() {
  ScriptApp.newTrigger('main')
  .timeBased()
  .everyDays(1)
  .atHour(9)
  .create();
}