if statment not making decision google script

my If statement if not making the decision to see if "rb" is in the set horizontal cells

I know this script is very ruff and there would be much greater ways to do this type of lookup but it is my first time coding. if someone could help with my code or even suggest better ways to do this i will do the research, it would be really appreciated

{
function sortAndSeperate() {
 var i = 3;
 var days = 11
 var d =SpreadsheetApp.getActiveSpreadsheet().getSheetByName("Coming Up work").getRange(2, 11);
 var sheet1 = SpreadsheetApp.getActiveSpreadsheet().getSheetByName("Coming Up work");
 var worker = SpreadsheetApp.getActiveSpreadsheet().getSheetByName("Reuben");
 var rangeMonday =sheet1.getRange(i,1,1,10)
 //var rangeTuesday=sheet1.getRange(row, column, numRows, numColumns)
 var copyrange = worker.getRange(i - 1, 1, 1, 10)

 
 
 if (rangeMonday = "rb") {
 var paste =SpreadsheetApp.getActiveSpreadsheet().getSheetByName("Coming Up work").getRange(i,1,1,10).copyTo(copyrange)
 var dateis = SpreadsheetApp.getActiveSpreadsheet().getSheetByName("Coming Up work").getRange(2 , days )
 var paste2 = SpreadsheetApp.getActiveSpreadsheet().getSheetByName("Reuben").getRange(i - 1,5)
 var paste3 = SpreadsheetApp.getActiveSpreadsheet().getSheetByName("Reuben").getRange(i - 1,6)
 dateis.copyTo(paste2)
 dateis.copyTo(paste3)
 }
  else {
   Logger.log('It is finished.');
 }