Conditionals

if / else

if (x > 0) {
    console.log("positive")
} else {
    console.log("negative or zero")
}

else if

if (x > 100) {
    console.log("large")
} else if (x > 0) {
    console.log("small")
} else {
    console.log("zero or negative")
}

Single line

if (x == 42) { console.log("correct!") }