Copy Down - Google Apps Script

CopyDown.js

function CopyDown() {
  var sheet = SpreadsheetApp.getActive();
  sheet.getCurrentCell().getNextDataCell(SpreadsheetApp.Direction.DOWN).activate();
  var currentCell = sheet.getCurrentCell();
  currentCell.activateAsCurrentCell();

  var rangeEnd = (sheet.getSelection().getNextDataRange(SpreadsheetApp.Direction.DOWN).getLastRow()) - currentCell.getRow();
  var range = sheet.getActiveSheet().getRange(currentCell.getRow(), currentCell.getColumn(), rangeEnd);

  currentCell.copyTo(range, SpreadsheetApp.CopyPasteType.PASTE_VALUES, false);
};