About the conditional operator and alternative syntax

If you like shortcuts, you can use the conditional (?:) operator, also called conditional expressions. The conditional operator lets you convert simple if..else statements into a single line of code. The operator helps decrease the amount of code you write while accomplishing the same thing, but it also tends to make your ActionScript more difficult to read.

The following condition is written in long hand, and checks whether the variable numTwo is greater than zero, and returns the result of numOne/numTwo or a string of carrot:

var numOne:Number = 8;
var numTwo:Number = 5;
if (numTwo > 0) {
  trace(numOne / numTwo); // 1.6
} else {
  trace("carrot");
}

Using a conditional expression, you would write the same code using this format:

var numOne:Number = 8;
var numTwo:Number = 0;
trace((numTwo > 0) ? numOne/numTwo : "carrot");

As you can see, the shortened syntax reduces readability, and so it is not preferable. If you must use conditional operators, place the leading condition (before the question mark [?]) inside parentheses. This helps improve the readability of your ActionScript. The following code is an example of ActionScript with improved readability:

var numOne:Number;
(numOne >= 5) ? numOne : -numOne;

You can write a conditional statement that returns a Boolean value, as the following example shows:

if (cartArr.length > 0) {
  return true;
} else {
  return false;
}

However, compared with the previous code, the ActionScript in the following example is preferable:

return (cartArr.length > 0);

The second snippet is shorter and has fewer expressions to evaluate. It's easier to read and understand.

When you write complex conditions, it is good form to use parentheses [()] to group conditions. If you do not use parentheses, you (or others working with your ActionScript) might run into operator precedence errors. For more information on operator precedence, see About operator precedence and associativity.

For example, the following code does not use parentheses around the condition:

if (fruit == "apple" && veggie == "leek") {}

The following code uses good form by adding parentheses around conditions:

if ((fruit == "apple") && (veggie == "leek")) {}

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