https://github.com/briancavalier/fx-ts

Computational environments and effects for TypeScript
https://github.com/briancavalier/fx-ts

algebraic-effects effects functional-programming typescript

Last synced: 2 months ago
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Computational environments and effects for TypeScript

• Host: GitHub
• URL: https://github.com/briancavalier/fx-ts
• Owner: briancavalier
• Created: 2019-11-13T13:43:54.000Z (about 5 years ago)
• Default Branch: master
• Last Pushed: 2023-01-24T01:40:50.000Z (almost 2 years ago)
• Last Synced: 2024-10-20T07:45:55.141Z (2 months ago)
• Topics: algebraic-effects, effects, functional-programming, typescript
• Language: TypeScript
• Homepage:
• Size: 2.17 MB
• Stars: 59
• Watchers: 5
• Forks: 7
• Open Issues: 23
• Metadata Files:
  • Readme: README.md

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• awesome-list - fx-ts

README

        
fx-ts


Capabilities & Effects for TypeScript




  Features • Install • Examples • Documentation



## Features

* **Do-notation for effects**: Write _imperative-looking_ code that's fully referentially transparent

* **Asychronous effects with cancelation**: Seamlessly mix synchronous and asynchronous effects without worry

* **Effect inference**: Effects can be inferred without explicit type annotations

* **Extensible**: Implement new effects in user land

* **Testable**: Code to interfaces, and easily use different implementations for development, production, and testing

* **Efficient**: Synchronous and Asynchronous effects run in _constant stack_

## Install

```shell

npm install --save fx-ts

```

## Examples

These examples are intended to be run against master using ts-node.  For example:

```sh

$ ./node_modules/.bin/ts-node -O '{ "module": "commonjs" }' ./examples/echo-console.ts

```

* [echo-console](examples/echo-console.ts): A simple read-print loop. A good introduction to the basics of capabilities and effects.

* [fp-to-the-max](examples/fp-to-the-max-1.ts): A more involved example number guessing game example from https://www.youtube.com/watch?v=sxudIMiOo68

This example runs on AWS Lambda.  [**If you have a serverless account and have setup your AWS credentials**](https://www.serverless.com/framework/docs/getting-started#set-up-your-free-pro-account), you can deploy it using `serverless`:

```sh

$ cd examples/lambda-pets

$ ./node_modules/.bin/serverless deploy

```

* [lambda-pets](examples/lambda-pets): A realistic AWS Lambda application that shows adoptable pets near the user's IP Address using https://ipstack.com and https://petfinder.com

### Running the examples

The

## Documentation

Pure functions are easy to reason about and test because they aren't entangled with the environment in which they're called. They always give the same answer for the same inputs. Nevertheless, useful programs need to interact with their environment.  They need access to databases, external services, or configuration, and need to perform effects like reading and writing files, updating databases, etc.

The goal of fx-ts is to help in writing programs that interact with their environment _and_ are easy to reason about and test.

```ts

// Abstract Print & Read capabilities

type Print = { print(s: string): Fx }

type Read = { read: Fx }

const main = doFx(function* () {

  const { print, read } = yield* get()

  while (true) {

    yield* print('> ')

    const s = yield* read

    yield* print(`${s}${EOL}`)

  }

})

const capabilities = {

  // ...Concrete implementation of Print and Read...

}

runFx(main(), capabilities)

```

## API

_Coming soon_

## Inspiration

* [koka](https://github.com/koka-lang/koka)

* [ZIO](https://zio.dev)

* [forgefx](https://github.com/briancavalier/forgefx)

* [ambient](https://github.com/briancavalier/ambient)