How to trigger an email notification when cell value is modified by function

Question

I would like to create a Google Sheets with event triggers. I\'m using Google Apps Script.

I succeeded, thanks to Stack Overflow, to create a Google Sheets with an autom

Answer 1

You can use a simple script that runs on a timer trigger and checks for any modification in a specific column in your sheet.

I use script like that for a lot of tasks, including calendar and sheets monitoring.

Below is a test code that works on column F, you have to run it once manually to create the scriptProperties value that I use to detect changes.

Then create a time trigger to run it every hour or any other timer value you find useful.

The only issue would be if you have a very long sheet, you could reach the length limit of the properties... (right now I don't remember the max length, will have to check ;-)

Code :

function checkColumnF() {
  var sh = SpreadsheetApp.getActiveSheet();
  var values = sh.getRange('F1:F').getValues().join('-');
  if(PropertiesService.getScriptProperties().getKeys().length==0){ // first time you run the script
    PropertiesService.getScriptProperties().setProperty('oldValues', values);
    return;
  }
  var oldValues = PropertiesService.getScriptProperties().getProperty('oldValues').split('-');
  var valuesArray = values.split('-');
  while (valuesArray.length>oldValues.length){
    oldValues.push('x'); // if you append some rows since last exec
  }
  Logger.log('oldValues = '+oldValues)
  Logger.log('current values = '+valuesArray)
  for(var n=0;n<valuesArray.length;n++){
    if(oldValues[n] != valuesArray[n]){ // check for any difference
      sendMail(n+1,valuesArray[n]);
    }
  }  
  PropertiesService.getScriptProperties().setProperty('oldValues', values);
}

function sendMail(row,val){
  Logger.log('value changed on row '+row+' value = '+val+' ,  mail sent');
  // uncomment below when you are sure everything runs fine to avoid sending dozens of emails while you test !
  //MailApp.sendEmail(Session.getActiveUser().getEmail(),'value changed in your sheet','Row '+row+' is now '+val);
}