Duplicate a row in Google Sheets.

duplicate-row.js

/* To use this in a Google Sheet:
1. Go to Tools > Script Editor.
2. Save the script.
3. Paste this script and click on the bug symbol.
4. Authorize the script.
5. Refresh the sheet.
*/

// global 
var ss = SpreadsheetApp.getActive();

function onOpen() {
  var menu = [{name:"Duplicate Row", functionName:"duplicateRow"}];
  ss.addMenu("Extras", menu);
}

/* Google Sheets does not copy formulas when inserting a row. Bogus.
While not exactly the same, this function duplicates the row, including the
formulas, and clears the cell in column 1 of the new row.
*/
function duplicateRow() {
  
  // Get the current sheet, row, and column.
  var sheet = ss.getActiveSheet();
  var row = ss.getActiveCell().getRow();
  var column = sheet.getLastColumn();
  
  // The range represents the current row from the first to last column.
  var range = sheet.getRange(row, 1, 1, column);
  
  //Browser.msgBox("Row: " + row + " Column: " + column);
  
  // Insert a blank row after the current one.
  // insertRowsBefore was producing strange results. The exact same code with insertRowsAfter seems to work as expected.
  sheet.insertRowsAfter(row, 1);
  
  // Copy the current row to the row we just added. When contentsOnly is true, a "paste values" occurs. We want the functions, so it's set to false.
  range.copyTo(sheet.getRange(row + 1, 1, 1, column), {contentsOnly:false});
  
  // Move to column 1 of the new row and clear the contents.
  new_range = sheet.getRange(row + 1, 1, 1, 1);
  ss.setActiveRange(new_range);
  ss.getActiveCell().clear();

}