[!NOTE]

This package is in a beta state and I'm excited for you to try it out!

I'd love your feedback! Share any suggestions, bug reports, feature requests, or general thoughts by filing an issue.

Install

$ npm i --save-dev type-to-fast-check fast-check

Usage

import * as fc from 'fast-check'
import typeToArb from 'type-to-fast-check'

type User = {
  firstName: string
  lastName: string
}

const userArb = typeToArb<User>()

fc.assert(
  fc.property(userArb, user => {
    // ...
  }),
)

The following code:

const userArb = typeToArb<User>()

Compiles to:

const userArb = fc.record({
  firstName: fc.string(),
  lastName: fc.string(),
})

You can pass any type to typeToArb!

Configure

1. Add the transformer plugin to your tsconfig.json:

   {
     "compilerOptions": {
       "plugins": [{ "transform": "type-to-fast-check/transformer" }]
     }
   }

2. Set up ts-patch to apply the configured plugin:

   1. Install:

      $ npm i --save-dev ts-patch

   2. Run for the first time:

      $ ts-patch install

   3. Configure to run after npm install:

      package.json

      {
        "scripts": {
          "prepare": "ts-patch install -s"
        }
      }

3. Configure your test runner to run tsc if it doesn't by default:

   • vitest (uses esbuild and doesn't run tsc)

     1. Install Rollup plugin:

        npm i --save-dev @rollup/plugin-typescript

     2. Add the plugin to your vitest.config.ts:

        vitest.config.ts

        import typescript from '@rollup/plugin-typescript'
        import { defineConfig } from 'vitest/config'
        
        export default defineConfig({
          // ...
          plugins: [typescript()],
        })

   • Send me PRs for configuring other test runners!

Roadmap

See the issue tracker! Share any suggestions, bug reports, feature requests, or general thoughts by filing an issue.

Contributing

Stars are always welcome!

For bugs and feature requests, please create an issue.

License

MIT © Tomer Aberbach