Optional is a wrapper for representing 'optional' (or 'nullable') objects who may not (yet) contain a valid value.

https://godoc.org/github.com/danielzhangy/optional

go get -u github.com/danielzhangy/optional

The purpose of the package is to provide a type-level solution for representing optional values instead of using nil in code. Instead traditional nil value or reference handling in Go is rough akin to

if obj != nil {
    // handle the non-nil object
} else {
    // handle the nil object
}

, optional package allows programmer to handle nil value or reference like

optional.Of("some object").
    IfPresent(func(i interface{}) {fmt.Println(i)})

.

Using optional.Absent() to create an empty Optional,

opt := Absent()
fmt.Println(opt)

// Example output:
// &{}

, or using optional.Of() to create an optional with given non-nil value,

opt := Of(1)
fmt.Println(opt)

// Example output:
// &{1}

. If you not sure that the value if nil or not, you can use optional.OfNilable() to create, it will generate a present or absent instance depended on the given value is non-nil or not.

opt1 := OfNilable(1)
fmt.Println("opt1: ", opt1)
opt2 := OfNilable(nil)
fmt.Println("opt2: ", opt2)

// Example output:
// opt1:  &{1}
// opt2:  &{}

Read the package documentation for more information.

We welcome pull requests, bug fixes and issue reports. With that said, the bar for adding new symbols to this package is intentionally set high.

Before proposing a change, please discuss your change by raising an issue.

MIT License