Break loop on null value

Question

I have one source Google Sheet that copies to a number of different Google Sheets for different students. The information copied is for different subjects, each a different sheet on the student's personal Sheets file.

The source sheet is set up to cope with differently sized classes, but my problem is trying to break the code when it reaches a section with no information. I don't know why my break statement is not working, since I know that copysheet is null as it results in an error every time the code runs.

function cloneGoogleSheet() {
  //select source sheet
  var sourcesheet = SpreadsheetApp.openById('some id');

  var j;
  for (var j = 1; j < 36; j++) {
    //select student sheets to copy to
    var studentid = sourcesheet.getSheetByName("Sheet11")
        .getRange(j, 2).getValue();

    var i;
    for (var i = 1; i < 14; i++) { 
      //select subject name for referencing different sheets
      var subject = sourcesheet.getSheetByName("Sheet6")
          .getRange(i + 1, 7 * j - 5).getValue();

      //find correct subject sheet on student sheet
      var copysheet = SpreadsheetApp.openById(studentid).getSheetByName(subject);

      if (copysheet != null) {break;}
      else {
        //copy "importrange" formula from sourcesheet
        var info = sourcesheet.getSheetByName("Sheet6")
            .getRange(i + 1, 7 * j).getValue();

        //copy teacher name from sourcesheet
        var teachername = sourcesheet.getSheetByName("Sheet6")
            .getRange(i + 1, 7 * j - 4).getValue();  

        //copy student name
        var studentname = sourcesheet.getSheetByName("Sheet6")
            .getRange(2, 7 * j - 6).getValue();  

        //paste "importrange" formula into student sheet 
        copysheet.getRange(6, 2).setValue(info);

        //paste teacher name into student sheet
        copysheet.getRange(3, 2).setValue(teachername);

        //paste student name into student sheet
        copysheet.getRange(1, 2).setValue(studentname);
      }
    }
  }
}

Answer 1

Change

if (copysheet != null) {break;}

to

if (copysheet == null) {break;}