How do you use the ? : (conditional) operator in JavaScript?

Question

In simple words, what is the ?: (conditional, "ternary") operator and how can I use it?

Answer 1

It's a little hard to google when all you have are symbols ;) The terms to use are "JavaScript conditional operator".

If you see any more funny symbols in JavaScript, you should try looking up JavaScript's operators first: Mozilla Developer Center's list of operators. The one exception you're likely to encounter is the $ symbol.

To answer your question, conditional operators replace simple if statements. An example is best:

var insurancePremium = age > 21 ? 100 : 200;

Instead of:

var insurancePremium;

if (age > 21) {
    insurancePremium = 100;
} else {
    insurancePremium = 200;
}