Google Sheets app script : How to send email on change in dropdown values?

Question

We have two sheets:

1. Sheet1 - It has one column & 10,000 rows with drop-down values - "approved" and "not approved".
2. Sheet2 - It has email-related details ie email, subject, message-approved, message-not-approved.

I want to send an automatic email if the drop-down value is changed. I want to send message-approved if someone changes Sheet1 dropdown selection to "approved" and message-not-approved if it is changed to "not approved".

I have been able to successfully send the email message when i run it in script editor but it is not triggering on drop down change. I understand that i need to use onedit trigger but not sure how to do that. Any help is appreciated. Here is the code.

function sendEmail(){

var ss1 = SpreadsheetApp.getActiveSpreadsheet();
var sheet1 = ss1.getSheetByName('Sheet1');
var valueToCheck = sheet1.getRange("A2").getValue();

if(valueToCheck == "approved"){
  var ss = SpreadsheetApp.getActiveSpreadsheet();
  var sheet2=ss.getSheetByName('Sheet2');
  var emailAddress = sheet2.getRange(2,1).getValue();
  var subject = sheet2.getRange(2,2).getValue();
  var message = sheet2.getRange(2,3).getValue();
  MailApp.sendEmail(emailAddress, subject, message);
}
else{
  var ss = SpreadsheetApp.getActiveSpreadsheet();
  var sheet2=ss.getSheetByName('Sheet2');
  var emailAddress = sheet2.getRange(2,1).getValue();
  var subject = sheet2.getRange(2,2).getValue();
  var message = sheet2.getRange(2,4).getValue();
  MailApp.sendEmail(emailAddress, subject, message);
}

}

Answer 1

Explanation:

• Make sure you take full advantage of the event object e .

• Because your function uses MailApp which is a service that needs authorization, you can only use an installable onEdit trigger to execute as an onEdit function.

• You can either create the installable trigger manually or programmatically. In the solution below, I show you the way to execute it programatically.

Solution:

Execute only and once the function create_onEdit and then upon user edits on cell A2 in Sheet1 , the script will send emails.

// execute create_onEdit only and once 
function create_onEdit(){
    ScriptApp.newTrigger('sendEmail')
    .forSpreadsheet(SpreadsheetApp.getActive())
    .onEdit()
    .create(); 
}

// this function should never be executed manually!


function sendEmail(e){
  const ss = e.source;
  const arng = e.range;
  const ash = arng.getSheet();
  const row = arng.getRow();
  const col = arng.getColumn();
  // trigger upon edits in Sheet1 and A2 till A10000
  if(ash.getName()=="Sheet1" && row>=2 && row<=10000 && col == 1){
    if(arng.getValue() == "approved"){
      const sheet2=ss.getSheetByName('Sheet2');
      const emailAddress = sheet2.getRange(2,1).getValue();
      const subject = sheet2.getRange(2,2).getValue();
      const message = sheet2.getRange(2,3).getValue();
      MailApp.sendEmail(emailAddress, subject, message);
    }
    else{
      const sheet2=ss.getSheetByName('Sheet2');
      const emailAddress = sheet2.getRange(2,1).getValue();
      const subject = sheet2.getRange(2,2).getValue();
      const message = sheet2.getRange(2,4).getValue();
      MailApp.sendEmail(emailAddress, subject, message);
    }
  }
}

Be careful:

• You should never execute sendEmail(e) manually as it will drop undefined errors. This function is a trigger function and it is meant to be automatically executed (triggered) upon user edits.

• The function create_onEdit is responsible for creating the trigger, so you only need to execute that once and you are ready to go.