Best way to prevent/handle divide by 0 in javascript
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.
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 /=
.
Off the top of my head you could:
- Check the user input to see if the denominator is zero (or evaluates to zero, depending on what your script actually does).
- Check if the result of the action
isFinite()
and if not then handle appropriately.
what would be the best way to handle such a situation so as to not prevent other scripts from executing
Division by zero doesn't seem to prevent other scripts from execution in JavaScript:
var a = 20;
var b = 0;
var result = a/b;
console.log(result); // returns Infinity
If you want something different to happen in case of division by zero, you could use
function divideIfNotZero(numerator, denominator) {
if (denominator === 0 || isNaN(denominator)) {
return null;
}
else {
return numerator / denominator;
}
}
Hope this is useful
(denominator != 0 ? numerator/denominator : Infinity)
or whatever value you want to put at the end.
Greetings.