Lucky is a serverless plugin that generates JSON Schema's from Yup Validators Schemas.

You can transform a Yup Validator into a JSON Schema:

Note: Available only in Yup Validators using require imports and module.exports.

Validator

const { object, string, number } = require('yup')
const userValidation = object().shape({ email: string(), age: number() })

module.exports = userValidation

JSON Schema

{
  "type": "object",
  "properties": {
    "email": { "type": "string", "example": ""},
    "age": { "type": "number", "example": 10 }
  },
  "example": {}
}

How it works

Lucky generates many JSON Schema's from a specific path with Yup Validators, you can set the path for validators and get the output JSON files, Lucky also updates your documentation, adding the new generated models, only if its needed.

It's strongly recommended that you use a documentation plugin for your serverless app and enable it to use Lucky, an awesome plugin is: serverless-openapi-documenter

Installation

Install via npm in the root of your serverless app:

npm install serverless-lucky --save-dev

You can also install via yarn:

yarn add serverless-lucky -D

Add the plugin to the plugins section in your serverless serverless.yml:

plugins:
  - serverless-lucky

Configuration

Lucky configurations must be defined under custom.lucky in the serverless.yml file before they can be used in the functions' configs:

custom:
  lucky:
    validatorsBasePath: src/validations # Specify your validator's location.
    outputPath: docs/models # Specify where you want to generate the output files.
    useExamples: false # Default, set to true if JSON models should have an example property.
    inlineDocs: false # Default, set to true if your documentation don't use an external Yaml.

Note: Paths are relative to the root app folder.

Then, in your function, specify the httpApi.lucky

get-hello-world:
    handler: helloWorld/get.handler
    events:
      - httpApi:
          method: get
          path: /hello
          lucky:
            schema: hello/getValidator.js # Yup Validator File
            contentType: application/json # Default
            folders:
              - hello
              - hello/new

Note: Folder's array only uses unique values.

Generate JSON Schema's

To run, execute the command: sls lucky, the following message will be showed, if successful:

Lucky on get-hello-world: schema created in .../docs/models/hello/get.json

Another message will be followed about the same file in another folder, according to array's folder:

Lucky on get-hello-world: schema created in .../docs/models/hello/new/get.json

Yaml documentation

Lucky updates your documentation Yaml file before the creation of new JSON schemas, adding a reference to new the schema with default name, schema location, description and contentType.

Before:

documentation:
  version: '1'
    title: 'My API'
    description: 'This is my API'
    termsOfService: https://google.com
    externalDocumentation:
      url: https://google.com
      description: A link to google
    servers:
      url: https://example.com:{port}/
      description: The server
      variables:
        port:
          enum:
            - 4000
            - 3000
          default: 3000
          description: The port the server operates on
  models: {}

After:

documentation:
  version: '1'
    title: 'My API'
    description: 'This is my API'
    termsOfService: https://google.com
    externalDocumentation:
      url: https://google.com
      description: A link to google
    servers:
      url: https://example.com:{port}/
      description: The server
      variables:
        port:
          enum:
            - 4000
            - 3000
          default: 3000
          description: The port the server operates on
  models: 
    - name: GetHelloWorld
      description: ""
      contentType: application/json
      schema: ${file(docs/models/hello/get.json)}

Using folders property

One interesting concept in Lucky is that you also can use folders to create groups and organize the output schema files, specifying the same folder by different functions.

functions:
  get-hello-world:
    handler: helloWorld/get.handler
    events:
      - httpApi:
          method: get # Output file name
          path: /hello
          lucky:
            schema: hello/getValidator.js # Yup Validator File
            folders: 
            - hello # Same folder or 'group' as create-hello-world
   create-hello-world:
    handler: helloWorld/post.handler
    events:
      - httpApi:
          method: post # Output files names are the method of a function
          path: /hello
          lucky:
            schema: hello/createValidator.js # Yup Validator File
            folders: 
            - hello # Same folder or 'group' as get-hello-world

Note: It will create 2 files, post.json and get.json, located in docs/models/hello folder, according to outputPath.

License

MIT