opt

func (Opt[T]) MarshalJSON ¶

func (o Opt[T]) MarshalJSON() ([]byte, error)

MarshalJSON implements the json.Marshaler interface, it marshals the Opt struct, if it is None, it returns JSON's null, otherwise it tries to marshal the underlying value, if it fails, the error is returned.

func (Opt[T]) String ¶

func (o Opt[T]) String() string

String implements the fmt.Stringer interface, it returns the string "<none>" if the Opt is None, otherwise it returns the string representation of the underlying value, using fmt.Sprint.

func (*Opt[T]) UnmarshalJSON ¶

func (o *Opt[T]) UnmarshalJSON(b []byte) error

UnmarshalJSON implements the json.Unmarshaler interface, it unmarshals the value into the Opt struct, if the input is JSON's null, the Opt is set to None, otherwise it tries to unmarshal the value into the underlying type, if it fails, the Opt is set to None and the error is returned.

func (Opt[T]) Unwrap ¶

func (o Opt[T]) Unwrap() (T, bool)

Unwrap unpacks the Opt struct and returns its components, a common assertion should be done, it may be done in the following way:

val, ok := opt.Unwrap()
if !ok {
	// handle noneness
}

Since this a non-build-in function, the ok return cannot be ommited.