openapi-typescript-validator

openapi-typescript-validator

Generate typescript with ajv validation based on openapi schemas

• What does this do?
• Getting started
• Documentation
  • generate

What does this do?

This package will convert your openapi 3.0 spec to:

• Typescript models
• Decoders which validate your models against a JSON schema

Example

This schema (note: also works with JSON based schema's)

components:
  schemas:
    User:
      type: object
      properties:
        id:
          type: string
        name:
          type: string
      required: ['id']

Will convert to:

export interface User {
  id: string;
  name?: string;
}

And will generate a decoder:

// user will be of type User if the JSON is valid
const user = UserDecoder.decode(json);

If the JSON is invalid, it will throw an error:

const user = UserDecoder.decode({
  id: 1
});

// User: /id: should be string. JSON: {"id":1}

References

References als work, this schema

{
  "components": {
    "schemas": {
      "Screen": {
        "type": "object",
        "properties": {
          "components": {
            "type": "array",
            "items": { "$ref": "#/components/schemas/Component" }
          }
        },
        "required": [ "components" ]
      },

      "Component": {
        "anyOf": [
          { "$ref": "#/components/schemas/TitleComponent" },
          { "$ref": "#/components/schemas/ImageComponent" }
        ]
      },

      "TitleComponent": {
        "type": "object",
        "properties": {
          "type": {
            "type": "string",
            "enum": ["title"]
          },
          "title": {
            "type": "string"
          },
          "subtitle": {
            "type": "string",
            "nullable": true
          }
        },
        "required": [ "type", "title" ]
      },

      "ImageComponent": {
        "type": "object",
        "properties": {
          "type": {
            "type": "string",
            "enum": ["image"]
          },
          "url": {
            "type": "string"
          }
        },
        "required": [ "type", "url" ]
      }
    }
  }
}

will generate

export type Component = TitleComponent | ImageComponent;

export interface Screen {
  components: Component[];
}
export interface TitleComponent {
  type: "title";
  title: string;
  subtitle?: string | null;
}
export interface ImageComponent {
  type: "image";
  url: string;
}

Custom builder

We also created a way to define your JSON schema a bit easier. The example above can also be written as:

Example: custom-schema.js

const { anyOf, array, constant, nillable, object, string } = require('openapi-typescript-validator');

const types = {};

types.Screen = object({
  components: array('Component'),
})

types.Component = anyOf(['TitleComponent', 'ImageComponent']);

types.TitleComponent = object({
  type: constant('title'),
  title: string,
  subtitle: nillable(string),
});

types.ImageComponent = object({
  type: constant('image'),
  url: string,
});

module.exports = { types }

Just call generate with schemaType: custom.

See src/builder.ts for all helpers which can be used.

Getting started

Install the package

npm i openapi-typescript-validator --save-dev

We use ajv for the decoders

npm i ajv

Your tsconfig.json file will need to be able to resolve the json files.

"resolveJsonModule": true

Create a node script called generate-schemas.js

const path = require('path');
const { generate } = require('openapi-typescript-validator');

generate({
  schemaFile: path.join(__dirname, 'myswagger.yaml'),
  schemaType: 'yaml',
  name: 'api',
  directory: path.join(__dirname, '/generated')
})

and run node generate-schemas.js

Documentation

generate

generate can be called with GenerateOptions

param	required	description
schemaFile	true	file location of the schema.
schemaType	true	yaml, json or custom
name	true	prefix for the generated files
directory	true	string or string[] location(s) where the output files will be stored.
prettierOptions	false	See Prettier Options