Custom google sheets apps script function to reduce value to N significant digits

sigDigits.gs

/**
 * @param {A1} value The value which should be reduced to n significant digits. E.g. 668951.12345
 * @param {3} nDigits Number of significant digits in cell. Default 3.
 * @return The value of a cell with N significant digits. E.g. 669000
 * @customfunction
 */
function sigDigits(value, nDigits) {
  var value = value || 668951.12345
  var nDigits = nDigits || 3
  valueRounded = +value.toFixed(0)
  lengthRounded = String(valueRounded).length
//   Logger.log("Rounded value: "+ valueRounded)
  var multiplier = 10**(lengthRounded - nDigits)
//   Logger.log("Multiplier for nDigits: "+ multiplier)
  value = valueRounded / multiplier
  value = +value.toFixed(0)
  value = value * multiplier
//   Logger.log("Result value: "+ value)
  return value
}