JSON typedef infer

This is a port of json-typedef-infer for Go. The reason for porting this is that I was in need of JTD inference from code and not as a CLI tool.

For more information about JSON Typedef and its RFC and how to use different kind of hints see json-typedef-infer.

Usage

See examples directory for runnable examples and how to infer JTD. If you want to infer a primitive Go type such as a string or map[string]any, you can use Infer:

schema := NewInferrer(WithoutHints()).
    Infer("my-string").
    IntoSchema()
// {
//   "type": "string"
// }

schema := NewInferrer(WithoutHints()).
    Infer(map[string]any{
        "age":  52,
        "name": "Joe",
    }).
    IntoSchema()
// {
//   "properties": {
//     "age": {
//       "type": "uint8"
//     },
//     "name": {
//       "type": "string"
//     }
//   }
// }

If you have one or more rows of JSON objects or lists as strings you can pass them to the shorthand function InferStrings. This will create an Inferrer and call Infer repeatedly on each row after deserializing it to a Go map. This is the recommended way to infer the schema even if you just have a single line.

rows := []string{
    `{"name":"Joe", "age": 52, "something_optional": true, "something_nullable": 1.1}`,
    `{"name":"Jane", "age": 48, "something_nullable": null}`,
}
schema := InferStrings(rows, WithoutHints()).IntoSchema()
// {
//   "properties": {
//     "age": {
//       "type": "uint8"
//     },
//     "name": {
//       "type": "string"
//     },
//     "something_nullable": {
//       "nullable": true,
//       "type": "float64"
//     }
//   },
//   "optionalProperties": {
//     "something_optional": {
//       "type": "boolean"
//     }
//   }
// }

CLI tool

There's not really a need for yet another CLI tool since the original jtd-infer project contains one, but since it was just a couple of lines to achieve this there's a CLI tool bundled here as well.

Installation

go install github.com/bombsimon/jtd-infer-go/cmd/jtd-infer-go@latest

CLI usage

The CLI tool reads from STDIN so something like this is the intended usage.

› echo '{"foo": "bar", "biz": 1}' | jtd-infer-go
{
  "properties": {
    "biz": {
      "type": "uint8"
    },
    "foo": {
      "type": "string"
    }
  }
}

› cat example.json
{"name":"Joe", "age": 52, "something_optional": true, "something_nullable": 1.1}
{"name":"Jane", "age": 48, "something_nullable": null}

› cat example.json | jtd-infer-go
{
  "properties": {
    "age": {
      "type": "uint8"
    },
    "name": {
      "type": "string"
    },
    "something_nullable": {
      "nullable": true,
      "type": "float64"
    }
  },
  "optionalProperties": {
    "something_optional": {
      "type": "boolean"
    }
  }
}

› jtd-infer-go < example.json
{
  "properties": {
    "age": {
      "type": "uint8"
    },
    "name": {
      "type": "string"
    },
    "something_nullable": {
      "nullable": true,
      "type": "float64"
    }
  },
  "optionalProperties": {
    "something_optional": {
      "type": "boolean"
    }
  }
}