@effect/io

What is @effect/io?

@effect/io is a library for building robust, type-safe, and composable applications in TypeScript. It provides a powerful set of tools for managing side effects, concurrency, and error handling in a functional programming style.

What are @effect/io's main functionalities?

Effect Management

This feature allows you to create and manage effects, which are computations that can produce values or perform side effects. The example demonstrates creating a simple effect that succeeds with the value 42 and then running it.

const { Effect } = require('@effect/io');

const effect = Effect.succeed(42);
effect.run().then(console.log); // Outputs: 42

Error Handling

This feature provides robust error handling capabilities. The example shows how to create an effect that fails with an error and how to handle that error when running the effect.

const { Effect } = require('@effect/io');

const effect = Effect.fail(new Error('Something went wrong'));
effect.run().catch(console.error); // Outputs: Error: Something went wrong

Concurrency

This feature allows you to compose and run effects concurrently. The example demonstrates combining two effects that succeed with values 1 and 2, respectively, and running them together.

const { Effect } = require('@effect/io');

const effect1 = Effect.succeed(1);
const effect2 = Effect.succeed(2);
const combinedEffect = Effect.zip(effect1, effect2);
combinedEffect.run().then(console.log); // Outputs: [1, 2]

Resource Management

This feature provides tools for managing resources that need to be acquired and released. The example shows how to create a resource, use it in an effect, and ensure that cleanup is performed afterward.

const { Effect, Resource } = require('@effect/io');

const resource = Resource.make(
  Effect.succeed('resource'),
  () => Effect.succeed(console.log('cleanup'))
);

resource.use(res => Effect.succeed(console.log(res))).run(); // Outputs: 'resource' and then 'cleanup'

Other packages similar to @effect/io

rxjs

RxJS is a library for reactive programming using Observables, to make it easier to compose asynchronous or callback-based code. Compared to @effect/io, RxJS focuses more on reactive streams and less on effect management and resource handling.

fp-ts

fp-ts is a library for functional programming in TypeScript. It provides many of the same functional programming constructs as @effect/io, but it is more focused on providing a comprehensive suite of functional programming utilities rather than specifically managing effects and concurrency.

redux-saga

redux-saga is a library that aims to make application side effects (e.g., asynchronous actions) easier to manage, more efficient to execute, and better at handling failures. It uses generator functions to handle side effects in a Redux application. While it shares some similarities with @effect/io in terms of managing side effects, it is more tightly coupled with Redux and less general-purpose.

README

WIP.

Docs: https://effect-ts.github.io/io

Changelog

0.0.66

Patch Changes

• a4a2c9a Thanks @patroza! - Add toString to Exceptions

• #198 59747ea Thanks @mikearnaldi! - Improve RuntimeFlags API

• #198 4448e99 Thanks @mikearnaldi! - Expose Schedule step and initial needed for custom schedules

• #198 b41507a Thanks @mikearnaldi! - Improve Layer API

• #199 7d0a9dc Thanks @patroza! - Fix missing _tag in built-in Exceptions

• #196 f1b8d74 Thanks @mikearnaldi! - Improve Deferred API

• #198 a941859 Thanks @mikearnaldi! - Defer standardization of OTEL Tracer

• #198 e20b27b Thanks @mikearnaldi! - Improve Reloadable API

• #198 411248e Thanks @mikearnaldi! - Type Queue functions as Effect constructors

• #201 02f1e57 Thanks @IMax153! - enhancements to Config and ConfigProvider

• #194 d4fdba5 Thanks @mikearnaldi! - Improve Ref, Ref.Syncronized and ScopedRef API

• #198 ed6ff39 Thanks @mikearnaldi! - Type Ref functions as Effect constructors

• #198 87d2ac0 Thanks @mikearnaldi! - Type Scope functions as Effect constructors

• #198 8f1c465 Thanks @mikearnaldi! - Improve FiberRefs API

• #198 44f1f6e Thanks @mikearnaldi! - Type Deferred functions as Effect constructors

• #198 fa08f70 Thanks @mikearnaldi! - Improve Hub API

• #198 b3b862f Thanks @mikearnaldi! - Type FiberRef functions as Effect constructors

• #198 61cf166 Thanks @mikearnaldi! - Add Layer.mergeAll

• #198 46171ba Thanks @mikearnaldi! - Improve Fiber unsafe api

• #197 3af5aa3 Thanks @mikearnaldi! - Prevent tacit usage of constructors with no arguments