Best way to prevent/handle divide by 0 in javascript

Question

What is the best way to prevent divide by 0 in javascript that is accepting user inputs. If there is no particular way to achieve this what would be the best way to handle such a situation so as to not prevent other scripts from executing?

Any insights are much appreciated.

Answer 1

There is no way to do that with the normal / and /= operators.

The best way to do what you want is with guards:

function notZero(n) {
  n = +n;  // Coerce to number.
  if (!n) {  // Matches +0, -0, NaN
    throw new Error('Invalid dividend ' + n);
  }
  return n;
}

and then do division like

numerator / notZero(denominator)

Alternatively you can always guard the output

function dividend(numerator, denominator) {
  var quotient = numerator / denominator;
  if (quotient !== quotient) { throw new Error(numerator + " / " + denominator); }
  return quotient;
}

but that loses the readability and expressiveness of /=.