goext/dataext/optional.go

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package dataext
import (
"encoding/json"
"errors"
)
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type JsonOpt[T any] struct {
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isSet bool
value T
}
// MarshalJSON returns m as the JSON encoding of m.
func (m JsonOpt[T]) MarshalJSON() ([]byte, error) {
if !m.isSet {
return []byte("null"), nil // actually this would be undefined - but undefined is not valid JSON
}
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return json.Marshal(m.value)
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}
// UnmarshalJSON sets *m to a copy of data.
func (m *JsonOpt[T]) UnmarshalJSON(data []byte) error {
if m == nil {
return errors.New("JsonOpt: UnmarshalJSON on nil pointer")
}
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m.isSet = true
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return json.Unmarshal(data, &m.value)
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}
func (m JsonOpt[T]) IsSet() bool {
return m.isSet
}
func (m JsonOpt[T]) IsUnset() bool {
return !m.isSet
}
func (m JsonOpt[T]) Value() (T, bool) {
if !m.isSet {
return *new(T), false
}
return m.value, true
}
func (m JsonOpt[T]) ValueOrNil() *T {
if !m.isSet {
return nil
}
return &m.value
}
func (m JsonOpt[T]) MustValue() T {
if !m.isSet {
panic("value not set")
}
return m.value
}