Changelog script for Google Sheets (see warning)

Changelog.gs

// WARNING: This will cause issues with the Undo function.
function onEdit(e) {
// Set sheet name (it must already exist):
var sheetName = "Changelog"

// e contains:
//  - authorized mode
//  - range
//  - source
//  - user
//  - value

// Get sheet
var sheet = SpreadsheetApp.getActiveSpreadsheet().getSheetByName(sheetName)

// Set values
var formattedDate = Utilities.formatDate(new Date(), "GMT-5", "yyyy-MM-dd  HH:mm:ss");
var source = "\"" + e.source.getSheetName() + "\""
var range = e.range.getA1Notation()
var values = [formattedDate, source, range, e.value]

// Set cells
var nextRow = sheet.getLastRow() + 1
for(var col = 1; col <= values.length; col++) {
sheet.getRange(nextRow, col).setValue(values[col-1])
}
}