Colorize cells based on editor - if-statement

Question

I try to make a script for Google Sheets, to see what do the editors modify.
This is my script:
function onEdit() {
var sheet = SpreadsheetApp.getActiveSheet();
var email = Session.getActiveUser().getEmail();
Logger.log(email);
var User1 = email.indexOf("user1#email.com");
var User2 = email.indexOf("user2#email.com");
Logger.log(User1);
Logger.log(User2);
if (User1 = -1.0){
sheet.getActiveCell().setBackground('#f4cccc')}
if (User2 = -1.0){
sheet.getActiveCell().setBackground('#c9daf8')}
}
Log looks correct:
11:42:08 AM Notice Execution started
11:42:10 AM Info user1#email.com
11:42:10 AM Info 0.0
11:42:10 AM Info -1.0
11:42:09 AM Notice Execution completed
But User1 & 2 got the same color(c9daf8). So I missed something.

Answer 1

Try the below code:
You need to use getEffectiveUser() instead of getActiveUser()
function onEdit() {
var sheet = SpreadsheetApp.getActiveSpreadsheet().getActiveSheet();
var email = Session.getEffectiveUser().getEmail();
Logger.log(email);
var User1 = "user1#email.com";
var User2 ="user2#email.com";
if (email == User1){
sheet.getActiveCell().setBackground('#f4cccc');
}
if (email == User2) {
sheet.getActiveCell().setBackground('#c9daf8');}
}
Reference: getEffectiveUser()
In case if applicable for the particular data range:
function onEdit() {
var sheet = SpreadsheetApp.getActiveSpreadsheet().getActiveSheet();
var dataRng = sheet.getActiveCell().getColumn();
var email = Session.getEffectiveUser().getEmail();
Logger.log(email);
var User1 = "user1#gmail.com";
var User2 = "user2#gmail.com";
if (email == User1 && (dataRng == 2 || dataRng == 3) ){
sheet.getActiveCell().setBackground('#f4cccc');
}
if (email == User2 && (dataRng == 2 || dataRng == 3)){
sheet.getActiveCell().setBackground('#c9daf8');
}
}