Home / Questions / 87658
Accepted
Eduardo Sebastian
Asked: 2020-07-18 20:31:41 +0800 CST 2020-07-18 20:31:41 +0800 CST

What is the error of this function?

  • 772

(function(){
    Math.sqrt(25) == 5 ? return true : return false;
})();

I only want to return trueif the root of 25gives 5, and otherwise return false.

javascript

2 Answers

  1. You must put the return at the beginning as follows:

    (function(){
  return (Math.sqrt(25)==5 ? true : false);
})();
    • 9
  2. Best Answer

    The error is solved by extracting the one returnfrom the options of the ternary operator, and putting it outside returning the result of the ternary operator (as @JavierPintor has already answered you in the other answer).

    The cause of the error is due to the fact that the ternary operator, being an operator, is not exactly like a conditional statement if. Since it is an operator, it has to return a value, obtaining said value from one of the possible options on both sides of :. These possible options must be expressions (combination of operators and operands) that will be evaluated to a value if chosen depending on the result of the condition. Therefore, since returnit does not form an expression that evaluates to a value, it is not supported.

    This is the solution:

    (function() {
    return Math.sqrt(25) == 5 ? true : false;
})();

    But, in cases like this, where you return trueor falsedepending on the result of a comparison, it's optimal if you directly return the result of the comparison that evaluates to trueor false. This way you avoid the ternary operator:

    (function() {
    return Math.sqrt(25) == 5;
})();
    • 1