Core Ternary - Lo — ContextQMD

A single-line if/else that returns ifOutput when condition is true, otherwise elseOutput.

result := lo.Ternary(true, "a", "b")
// result: "a"

result = lo.Ternary(false, "a", "b")
// result: "b"

// With numbers
age := 25
status := lo.Ternary(age >= 18, "adult", "minor")
// status: "adult"

// With complex expressions
x, y := 10, 20
max := lo.Ternary(x > y, x, y)
// max: 20

TernaryF - Function Form

Function form of Ternary. Lazily evaluates the selected branch to avoid unnecessary work or nil dereferences.

var s *string
str := lo.TernaryF(s == nil, func() string {
    return uuid.New().String()
}, func() string {
    return *s
})
// str: newly generated UUID (since s is nil)

// Example with expensive operations
str = "hello"
result := lo.TernaryF(s != nil, func() string {
    return *s // safe dereference only when s is not nil
}, func() string {
    return "default value"
})
// result: "hello"

// Performance benefit - only executes needed branch
result = lo.TernaryF(false, func() string {
    time.Sleep(1 * time.Second) // this won't execute
    return "slow operation"
}, func() string {
    return "fast operation" // only this executes
})
// result: "fast operation" (returns immediately)