Conditionals

• Evaluation
• if
• switch
• Ternary (?:)

Evaluation

Conditionals operate on bool values, but other values can implicitly convert to a bool value. The following table shows how this conversion takes place.

Type	Converts To
number	true if not NaN
string	true
object	return value of [[__bool
array	true
null	false
undefined	false
function	true

if

for (var i = 0; i <= 5; i++) {
    if (i == 1) {
        print('one');
    } else if (i == 2) {
        print('two');
    } else if (i == 3) {
        print('three');
    } else if (i == 4 || i == 5) {
        print('four or five');
    } else {
        print('something else');
    }
}

switch

The break statement can be used in branches to exit the switch statement. Branches do not allow fallthrough and have an implicit break before other cases.

for (var i = 0; i <= 5; i++) {
    switch (i) {
        case 1:
            print('one');
        case 2:
            print('two');
        case 3:
            print('three');
        case 4:
        case 5:
            print('four or five');
        default:
            print('something else');
    }
}

Ternary

The ternary operator (?:) is a conditional expression that is like an inline if..else block. The ternary operator can be used like this:

var a = 5;
var b = a >= 3 ? 10 : 0;

The same thing can be accomplished by doing this:

var a = 5;
var b;
if (a >= 3)
    b = 10;
else
    b = 0;