npm package discovery and stats viewer.

Discover Tips

  • General search

    [free text search, go nuts!]

  • Package details

    pkg:[package-name]

  • User packages

    @[username]

Sponsor

Optimize Toolset

I’ve always been into building performant and accessible sites, but lately I’ve been taking it extremely seriously. So much so that I’ve been building a tool to help me optimize and monitor the sites that I build to make sure that I’m making an attempt to offer the best experience to those who visit them. If you’re into performant, accessible and SEO friendly sites, you might like it too! You can check it out at Optimize Toolset.

About

Hi, 👋, I’m Ryan Hefner  and I built this site for me, and you! The goal of this site was to provide an easy way for me to check the stats on my npm packages, both for prioritizing issues and updates, and to give me a little kick in the pants to keep up on stuff.

As I was building it, I realized that I was actually using the tool to build the tool, and figured I might as well put this out there and hopefully others will find it to be a fast and useful way to search and browse npm packages as I have.

If you’re interested in other things I’m working on, follow me on Twitter or check out the open source projects I’ve been publishing on GitHub.

I am also working on a Twitter bot for this site to tweet the most popular, newest, random packages from npm. Please follow that account now and it will start sending out packages soon–ish.

Open Software & Tools

This site wouldn’t be possible without the immense generosity and tireless efforts from the people who make contributions to the world and share their work via open source initiatives. Thank you 🙏

© 2025 – Pkg Stats / Ryan Hefner

effect

v3.14.8

Published

The missing standard library for TypeScript, for writing production-grade software.

Downloads

6,698,332

Readme

effect Core Package

The effect package is the heart of the Effect framework, providing robust primitives for managing side effects, ensuring type safety, and supporting concurrency in your TypeScript applications.

Requirements

  • TypeScript 5.4 or Newer: Ensure you are using a compatible TypeScript version.

  • Strict Type-Checking: The strict flag must be enabled in your tsconfig.json. For example:

    {
      "compilerOptions": {
        "strict": true
        // ...other options
      }
    }

Installation

Install the core package using your preferred package manager. For example, with npm:

npm install effect

Documentation

Overview of Effect Modules

The effect package provides a collection of modules designed for functional programming in TypeScript. Below is a brief overview of the core modules:

| Module | Description | | -------- | -------------------------------------------------------------------------------------------------------------------------- | | Effect | The core abstraction for managing side effects, concurrency, and error handling in a structured way. | | Context | A lightweight dependency injection mechanism that enables passing services through computations without direct references. | | Layer | A system for managing dependencies, allowing for modular and composable resource allocation. | | Fiber | Lightweight virtual threads with resource-safe cancellation capabilities, enabling many features in Effect. | | Stream | A powerful abstraction for handling asynchronous, event-driven data processing. | | Schedule | A module for defining retry and repeat policies with composable schedules. | | Scope | Manages the lifecycle of resources, ensuring proper acquisition and release. | | Schema | A powerful library for defining, validating, and transforming structured data with type-safe encoding and decoding. |

For a comparison between effect/Schema and zod, see Schema vs Zod.