https://www.pbainbridge.co.uk/2018/12/get-column-by-name.html

Get column by name.gs

function getColByName(name) {
  
  // get column headers as an array to search through
  var headers = SpreadsheetApp.getActiveSpreadsheet().getSheetByName('Students').getDataRange().getValues().shift();
  
  // search array looking for specific text to return its position
  var colindex = headers.indexOf(name);
  
  return colindex+1;
  
}


function getColumnData() {
  
  /* calls 'getColByName' function and searches for 'forename' to then return the relevant column index as a number 
  stored as variable */
  var forename = getColByName('forename');
  Logger.log(forename);
  
  // get active spreadsheet
  var ss = SpreadsheetApp.getActiveSpreadsheet();
  
  // get active sheet
  var sheet = ss.getActiveSheet();
  
  // get active cell
  var activeCell = sheet.getActiveCell();
  
  // find current row for active cell
  var currentRow = activeCell.getRow();
  
  /* get student data
  get 'forename' by using previous 'getColByName' function (which specifies the startColumn value now) in the current
  row data via getRange(startRow, startColumn, numRows, numColumns) */
  var dataName = sheet.getRange(currentRow, forename, 1, 1).getValue();
  
}