Javascript 비교, If

이중 등호 vs 삼중 등호

1 == 1;  // true
1 == '1';  // true
0 == '';  // true
0 != '';  // false
null == undefined; //true

1 === '1';  // false
0 === false;  // false
1 !== '1';  // true

 

 

If

const age = prompt("Enter your age.");

if (age < 10 || age >= 65) {
    console.log("You are free");
} else if (age < 50) {
    console.log("You pay $20");
} else {
    console.log("You pay $10");
}

 

 

Switch

const day = 2;

switch (day) {
    case 1:
        console.log("Monday");
        break;

    case 2:
        console.log("Tuesday");
        break;

    case 3:
        console.log("Wednesday");
        break;

    default:
        console.log("I don't know");
}