I'm trying to convert the code below to a shorthand version with a ternary operator

     if (sum % 10 === 0) {
        return true;
     } else {
        return false;
      }

It works fine as is, but when I change it to

sum % 10 === 0 ? return true : return false; 

I get a syntax error, and when I change it to

sum % 10 === 0 ? true : false; 

it doesn't work as intended.

If anyone can enlighten me as to what's going on, I'd be much appreciated.

I'm trying to convert the code below to a shorthand version with a ternary operator

     if (sum % 10 === 0) {
        return true;
     } else {
        return false;
      }

It works fine as is, but when I change it to

sum % 10 === 0 ? return true : return false; 

I get a syntax error, and when I change it to

sum % 10 === 0 ? true : false; 

it doesn't work as intended.

If anyone can enlighten me as to what's going on, I'd be much appreciated.

• javascript
• return
• conditional-operator

• 5 return sum % 10 === 0 ? true : false; – Sajeeb Ahamed Commented Apr 16, 2020 at 8:03
• 4 Even return sum % 10 === 0 should be fine – Anurag Srivastava Commented Apr 16, 2020 at 8:03
• 2 return sun % 10 === 0; If the condition is true, will return true, if the condition is false, will return false. – KodeFor.Me Commented Apr 16, 2020 at 8:04
• 1 "If anyone can enlighten me..." -> Conditional (ternary) operator - JavaScript | MDN – Andreas Commented Apr 16, 2020 at 8:06

3 Answers 3

The expression (sum % 10 === 0) is boolean itself, so just return it:

return sum % 10 === 0

You can simply do:

return !(sum % 10)

if (sum % 10) === 0, then !(sum % 10) will return true, else false.

What you tried:

sum % 10 === 0 ? return true : return false; 

This does not work, because return is a statement and not an expression. A statement can not be used inside of an expression.

sum % 10 === 0 ? true : false; 

This works, but without a return statement, it is just an expression without using it.

Finally, you need to retur the result of the conditional (ternary) operator ?:, like

return sum % 10 === 0 ? true : false; 

For a shorter approach you could return the result of the parison without ternary.

return sum % 10 === 0;