Throwing custom exceptions and error messages in Google Sheets custom function?

Question

In Google Sheets (as with Excel, etc) if a user enters bad input into a formula, an error code will be printed in the offending cell and a small pop-up provides more detail

Answer 1

Use try...catch and the message property of the error object, then return the error message instead of throwing an error. I.E.:

/**
 *
 * @customfunction
 */
function myDiv(dividend,divisor){
  var quotient;
  try{
     quotient = dividend / divisor;
  } catch(error) {
     quotient = error.message;
  } finally {
     return quotient;
  }

}

Reference

• https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Statements/try...catch
• https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Error/Error

Answer 2

This is a reported problem.

Visit Issue 4422, star it to vote and for updates.

Answer 3

if (some_condition)
{
  // will end execution with error    
  throw 'Error. My custom error description.';
}