# json-schema-to-typescript [![Build Status][build]](https://circleci.com/gh/bcherny/json-schema-to-typescript) [![npm]](https://www.npmjs.com/package/json-schema-to-typescript) [![mit]](https://opensource.org/licenses/MIT)

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> Compile json schema to typescript typings

**[In Beta]**: Bug reports appreciated!

## Example

Input:
```json
{
  "title": "Example Schema",
  "type": "object",
  "properties": {
    "firstName": {
      "type": "string"
    },
    "lastName": {
      "type": "string"
    },
    "age": {
      "description": "Age in years",
      "type": "integer",
      "minimum": 0
    },
    "hairColor": {
      "enum": ["black", "brown", "blue"],
      "type": "string"
    }
  },
  "required": ["firstName", "lastName"]
}
```

Output:
```ts
export interface ExampleSchema {
  firstName: string;
  lastName: string;
  /**
   * Age in years
   */
  age?: number;
  hairColor?: "black" | "brown" | "blue";
}
```

## Installation

`npm install json-schema-to-typescript`

or, to install the `json-schema-to-typescript` CLI utility:

`npm install -g json-schema-to-typescript`

## Usage
### API

```js
import {compileFromFile} from 'json-schema-to-typescript'

fs.writeFileSync('dist/foo.d.ts', await compileFromFile('src/foo.json'))
```

### CLI
```
$ json-schema-to-typescript src/foo.json
... snipped output here, on stdout ...
$ json-schema-to-typescript src/foo.json dist/foo.d.ts
$
```

See [/example](example) for a fully working demo.

## Tests

`npm test`

## Todo

- [x] `title` => `interface`
- [x] Primitive types:
  - [x] array
  - [x] homogeneous array
  - [x] boolean
  - [x] integer
  - [x] number
  - [x] null
  - [x] object
  - [x] string
  - [x] homogeneous enum
  - [x] heterogeneous enum
- [x] Non/extensible interfaces
- [ ] Custom JSON-schema extensions
- [x] Nested properties
- [x] Schema definitions
- [x] [Schema references](http://json-schema.org/latest/json-schema-core.html#rfc.section.7.2.2)
- [x] Local (filesystem) schema references
- [ ] External (network) schema references
- [ ] Add support for running in browser
- [x] default interface name
- [ ] infer unnamed interface name from filename
- [x] `anyOf` ("union")
- [x] `allOf` ("intersection")
- [x] `additionalProperties` of type
- [ ] [`extends`](https://github.com/json-schema/json-schema/wiki/Extends)
- [x] `required` properties on objects ([eg](https://github.com/tdegrunt/jsonschema/blob/67c0e27ce9542efde0bf43dc1b2a95dd87df43c3/examples/all.js#L130))
- [ ] `validateRequired` ([eg](https://github.com/tdegrunt/jsonschema/blob/67c0e27ce9542efde0bf43dc1b2a95dd87df43c3/examples/all.js#L124))
- [x] literal objects in enum ([eg](https://github.com/tdegrunt/jsonschema/blob/67c0e27ce9542efde0bf43dc1b2a95dd87df43c3/examples/all.js#L236))
- [ ] referencing schema by id ([eg](https://github.com/tdegrunt/jsonschema/blob/67c0e27ce9542efde0bf43dc1b2a95dd87df43c3/examples/all.js#L331))
- [ ] clean up + refactor code

## Not expressible in TypeScript:

- `dependencies` ([single](https://github.com/tdegrunt/jsonschema/blob/67c0e27ce9542efde0bf43dc1b2a95dd87df43c3/examples/all.js#L261), [multiple](https://github.com/tdegrunt/jsonschema/blob/67c0e27ce9542efde0bf43dc1b2a95dd87df43c3/examples/all.js#L282))
- `divisibleBy` ([eg](https://github.com/tdegrunt/jsonschema/blob/67c0e27ce9542efde0bf43dc1b2a95dd87df43c3/examples/all.js#L185))
- [`format`](https://github.com/json-schema/json-schema/wiki/Format) ([eg](https://github.com/tdegrunt/jsonschema/blob/67c0e27ce9542efde0bf43dc1b2a95dd87df43c3/examples/all.js#L209))
- `multipleOf` ([eg](https://github.com/tdegrunt/jsonschema/blob/67c0e27ce9542efde0bf43dc1b2a95dd87df43c3/examples/all.js#L186))
- `maximum` ([eg](https://github.com/tdegrunt/jsonschema/blob/67c0e27ce9542efde0bf43dc1b2a95dd87df43c3/examples/all.js#L183))
- `minimum` ([eg](https://github.com/tdegrunt/jsonschema/blob/67c0e27ce9542efde0bf43dc1b2a95dd87df43c3/examples/all.js#L182))
- `maxItems` ([eg](https://github.com/tdegrunt/jsonschema/blob/67c0e27ce9542efde0bf43dc1b2a95dd87df43c3/examples/all.js#L166))
- `minItems` ([eg](https://github.com/tdegrunt/jsonschema/blob/67c0e27ce9542efde0bf43dc1b2a95dd87df43c3/examples/all.js#L165))
- `maxProperties` ([eg](https://github.com/tdegrunt/jsonschema/blob/67c0e27ce9542efde0bf43dc1b2a95dd87df43c3/examples/all.js#L113))
- `minProperties` ([eg](https://github.com/tdegrunt/jsonschema/blob/67c0e27ce9542efde0bf43dc1b2a95dd87df43c3/examples/all.js#L112))
- `not`/`disallow`
- `oneOf` ("xor", use `anyOf` instead)
- `pattern` ([string](https://github.com/tdegrunt/jsonschema/blob/67c0e27ce9542efde0bf43dc1b2a95dd87df43c3/examples/all.js#L203), [regex](https://github.com/tdegrunt/jsonschema/blob/67c0e27ce9542efde0bf43dc1b2a95dd87df43c3/examples/all.js#L207))
- `patternProperties` ([eg](https://github.com/tdegrunt/jsonschema/blob/67c0e27ce9542efde0bf43dc1b2a95dd87df43c3/examples/all.js#L97))
- `uniqueItems` ([eg](https://github.com/tdegrunt/jsonschema/blob/67c0e27ce9542efde0bf43dc1b2a95dd87df43c3/examples/all.js#L172))

## Further Reading

- JSON-schema spec: http://json-schema.org/latest/json-schema-core.html
- JSON-schema wiki: https://github.com/json-schema/json-schema/wiki
- JSON-schema test suite: https://github.com/json-schema/JSON-Schema-Test-Suite/blob/node
- TypeScript spec: https://github.com/Microsoft/TypeScript/blob/master/doc/spec.md