조건 (삼항) 연산자

function getFee(isMember) {
  return isMember ? "$2.00" : "$10.00";
}

console.log(getFee(true));
// Expected output: "$2.00"

console.log(getFee(false));
// Expected output: "$10.00"

console.log(getFee(null));
// Expected output: "$10.00"

condition ? exprIfTrue : exprIfFalse;

var age = 26;
var beverage = age >= 21 ? "Beer" : "Juice";
console.log(beverage); // "Beer"

let greeting = (person) => {
  let name = person ? person.name : `stranger`;
  return `Howdy, ${name}`;
};

console.log(greeting({ name: `Alice` })); // "Howdy, Alice"
console.log(greeting(null)); // "Howdy, stranger"

function example(…) {
    return condition1 ? value1
         : condition2 ? value2
         : condition3 ? value3
         : value4;
}

function example(…) {
    if (condition1) { return value1; }
    else if (condition2) { return value2; }
    else if (condition3) { return value3; }
    else { return value4; }
}