https://github.com/gomoni/null

Go null and undefined aware type wrapper
https://github.com/gomoni/null

generics go golang json

Last synced: 6 months ago
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Go null and undefined aware type wrapper

• Host: GitHub
• URL: https://github.com/gomoni/null
• Owner: gomoni
• License: bsd-3-clause
• Created: 2021-12-17T14:38:31.000Z (over 4 years ago)
• Default Branch: main
• Last Pushed: 2022-01-03T08:29:54.000Z (over 4 years ago)
• Last Synced: 2024-06-20T16:52:03.975Z (about 2 years ago)
• Topics: generics, go, golang, json
• Language: Go
• Homepage:
• Size: 16.6 KB
• Stars: 2
• Watchers: 2
• Forks: 0
• Open Issues: 0
• Metadata Files:
  • Readme: README.md
  • License: LICENSE

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README

          
[![License](https://img.shields.io/badge/License-BSD_3--Clause-blue.svg)](https://opensource.org/licenses/BSD-3-Clause)

# null

null is a Go library providing an easy to use interface to handle `null` value or missing key. `Type[T any]` implements `json.Marshaler` and `json.Unmarshaler` . Because of generics it works for any type which can be unmarshalled from/marshalled into JSON.

Marshalling of undefined is an error though.

# Usage

```go

// define struct with a wrapper type

var s struct {

    Key Type[int] `json:"key"`

}

// unmarshal as usual

err := json.Unmarshal(data, &s)

// access value via Value() method, which returns error for null and undefined cases

value, err := s.Key.Value()

```

| JSON           | Value  | Error        |

|----------------|--------|--------------|

|`{"key": 42}`   | `42`   | `nil`        |

|`{"key": null}` | _zero_ | ErrNull      |

|`{}`            | _zero_ | ErrUndefined |

# Build and test

install gotip (until go 1.18 release)

```bash

go install golang.org/dl/gotip@latest

gotip download

gotip test -v

```