@effect/data

What is @effect/data?

@effect/data is a functional programming library for JavaScript and TypeScript that provides a collection of data structures and utilities to work with immutable data, functional effects, and more. It aims to help developers write more predictable and maintainable code by leveraging functional programming principles.

What are @effect/data's main functionalities?

Immutable Data Structures

Provides immutable data structures like List, Map, and Set. These structures help in maintaining immutability in your code, making it easier to reason about state changes.

const { List } = require('@effect/data');

const list = List.of(1, 2, 3);
const newList = list.append(4);
console.log(newList.toArray()); // [1, 2, 3, 4]

Functional Effects

Allows you to work with functional effects, which are computations that can produce side effects. This helps in managing side effects in a controlled manner.

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

const effect = Effect.of(() => console.log('Hello, World!'));
effect.run();

Option and Either

Provides Option and Either types for handling optional values and computations that can fail, respectively. These types help in avoiding null or undefined values and managing errors more effectively.

const { Option, Either } = require('@effect/data');

const someValue = Option.some(42);
const noneValue = Option.none();

const rightValue = Either.right('Success');
const leftValue = Either.left('Error');

console.log(someValue.isSome()); // true
console.log(noneValue.isNone()); // true
console.log(rightValue.isRight()); // true
console.log(leftValue.isLeft()); // true

Pattern Matching

Supports pattern matching, which allows you to match values against patterns and execute code based on the matched pattern. This can make your code more expressive and concise.

const { match } = require('@effect/data');

const value = 2;
const result = match(value)
  .case(1, () => 'one')
  .case(2, () => 'two')
  .case(3, () => 'three')
  .default(() => 'unknown');

console.log(result); // 'two'

Other packages similar to @effect/data

immutable

The 'immutable' package provides persistent immutable data structures for JavaScript, such as List, Map, and Set. It is similar to @effect/data in terms of offering immutable data structures but does not include functional effects or pattern matching.

folktale

Folktale is a suite of libraries for generic functional programming in JavaScript. It includes data structures like Maybe and Either, similar to Option and Either in @effect/data. However, Folktale also provides utilities for asynchronous programming and algebraic data types.

ramda

Ramda is a practical functional library for JavaScript programmers. It focuses on providing utility functions for functional programming, such as currying, composition, and immutability. While it does not provide data structures like @effect/data, it complements it by offering a wide range of functional utilities.

README

Installation

To install the alpha version:

npm install @effect/data

Warning. This package is primarily published to receive early feedback and for contributors, during this development phase we cannot guarantee the stability of the APIs, consider each release to contain breaking changes.

Requirements

• TypeScript 4.8 or newer
• The strict flag enabled in your tsconfig.json file

{
  // ...
  "compilerOptions": {
    // ...
    "strict": true,
  }
}

Documentation (WIP)

• API Reference

License

The MIT License (MIT)

Changelog

0.5.1

Patch Changes

• #278 15644cf Thanks @jessekelly881! - Array: added getEquivalence

• #280 1a2021f Thanks @patroza! - fix(Context): add Tag<Tag<T>> issue