json-schema-to-typescript

Compile json schema to typescript typings

[In Beta]: Bug reports appreciated!

Example

Input:

{
  "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:

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

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 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
• [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
• [x] required properties on objects (eg)
• [ ] validateRequired (eg)
• [x] literal objects in enum (eg)
• [ ] referencing schema by id (eg)
• [ ] clean up + refactor code

Not expressible in TypeScript:

• dependencies (single, multiple)
• divisibleBy (eg)
• format (eg)
• multipleOf (eg)
• maximum (eg)
• minimum (eg)
• maxItems (eg)
• minItems (eg)
• maxProperties (eg)
• minProperties (eg)
• not/disallow
• oneOf ("xor", use anyOf instead)
• pattern (string, regex)
• patternProperties (eg)
• uniqueItems (eg)

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