Flow to gen

_Transforms flow type aliases into generators for property based testing_

Motivation

This Babel plugin attempts to alleviate the manual task of creating and maintaining fixtures/mocks by transforming all Flowtype type aliases
into generator functions for mock data. Additionally, it provides a framework for automatically generating random input for
typed functions and React components. If you're unfamiliar with generative or property based testing, please check out an implementation of
Quickcheck in your language of choice. Also look at
testcheck.js which is 100% compatible and wrapped by the runtime of this library.

By running this Babel transform on your code:
- all type aliases are transformed in testcheck.js generators
- all typed functions can immediately retrieve randomly generated inputs
- all typed React components can immediately retrieve randomly generated props

TODO:
- handle TypeofTypeAnnotation
- handle ExistentialTypeAnnotation
- handle recursive types
- handle Flow globally defined types
- handle React components

Demo?

DEMO!

Getting Started

babel-plugin-transform-flow-to-gen transforms your type aliases into functions
that create testcheck.js generators.

Usage

``js
import {sample, types} from 'babel-plugin-transform-flow-to-gen/api';

type Person = {
firstName: string,
lastName: string,
age: T
}

// use the generator static member to create samples
const personGen = Person(types.number());
sample(personGen, 20);
// [{
// "firstName": "9OY3o",
// "lastName": "fB",
// "age": 0
// },
// {
// "firstName": "8Hft5LwfK",
// "lastName": "51Vnn54vb9xHO",
// "age": 2
// },
// {
// "firstName": "7i59Sr35GAJiv626uiV",
// "lastName": "s7GIgEf",
// "age": 3
// },
// {
// "firstName": "Mys89F65i36n921",
// "lastName": "",
// "age": 1
// }, ...]

function setFirstName(person: Person, firstName: string) {
// ...
}

// returns an array of args for setFirstName
sample(setFirstName.asGenerator());
// [
// [{
// "firstName": "3o",
// "lastName": "j467DA",
// "age": 0
// }, "f02j"]
// , ...]
`

Installing

`js
yarn add babel-plugin-transform-flow-to-gen
``

License

MIT