10/05/2018: Now that all stable browsers support ES modules, the latest version of the jspm CDN has been released at jspm.io, fully-utilizing the native module loader. As a result, the previous version of the jspm CDN will be deprecated soon.

Project Status

jspm was first released in 2013 in order to align JavaScript module workflows with the module loader specification of the time, on top of which SystemJS is based. Since then, the loader spefication has been discontinued and broken out into separate module specification processes for JavaScript, the browser and NodeJS.

As a result, the design decisions of jspm need to be rebuilt to align with these current trends.

The first step of this process, updating the jspm CDN to modules has been launched at jspm.io. Work to update the jspm package manager and its associated tooling is taking place through aligning on SystemJS 2.0 and Rollup code splitting workflows.

The overall initiative here towards a jspm 2.0 is very much an uncertain work-in-progress depending on support and interest. Updates will be posted here over the coming months.

Summary

jspm is a package manager for the SystemJS universal module loader, built on top of the dynamic ES6 module loader
Load any module format (ES6, AMD, CommonJS and globals) directly from any registry such as npm and GitHub with flat versioned dependency management. Any custom registry endpoints can be created through the Registry API.
For development, load modules as separate files with ES6 and plugins compiled in the browser.
For production (or development too), optimize into a bundle, layered bundles or a self-executing bundle with a single command.

Docs

jspm 0.17 beta - Beta overview and guide
jspm 0.16 - Getting Started guide in the documentation

Articles / Videos

Choose ES6 Modules Today article with screencasts by Cody Lindley
ES6 Modules & React with SystemJS live coding presentation by Jack Franklin
JavaScript in 2015 article and screencast by Glen Maddern
JavaScript Modules and Dependencies with jspm tutorial by Jack Franklin
Package Management for ES6 Modules JSConf 2014 presentation introducing jspm by Guy Bedford

Project Overview

SystemJS

jspm package management is designed around the SystemJS dynamic ES6 loader.

RequireJS-style module loader with similar configuration and plugin system.
Built on top of the ES6 Module Loader polyfill, making it standards-compliant and future-friendly.

Note that SystemJS is built on top of a draft module loader specification that is subject to change.

jspm CLI

Uses flat version management to download into version-suffixed folders (eg jspm_packages/npm/[email protected]).
Shares versions between dependencies, upgrading or downgrading dependency resolutions within their supported ranges to minimize forks during install.
Because the installer understands the loader, modular code including loader plugins, works with a single install and a single require.

Read the CLI documentation on Github

Registries

jspm is designed to support any number of independent registries.

All packages are universally named to a registry with the syntax registry:[email protected].
When importing external modules, we refer to them with an alias like jquery, which maps to the universal name in the background.
Each package has its own map, allowing jquery to refer to different things for different packages and supporting multi-versions.

The following registries are currently supported:

npm:
- Most packages on npm will work naturally with full version management, with no further configuration necessary.
- The NodeJS builtins are provided by the same libraries used in Browserify.
GitHub:
- Packages on GitHub get their versions from semver tag names (with or without a v prefix).
- When a GitHub release for a given tag is provided, the release archive will be used instead of the repo.
- GitHub packages will benefit from jspm configuration being provided through the package.json or an override.

Registry

The jspm registry provides a convenience mapping from shortcut names into full registry names.

This allows for easier installation - jspm install jquery over jspm install github:components/jquery, and provides the default aliasing.

It also indicates packages which are jspm-compatible and makes it clear where the primary package source for jspm is (GitHub or npm).

Browse the registry

Version Management

jspm CLI implements shortest-path fork reduction during installs, while ensuring targets are at their latest patch versions to reduce bugs.

The version solution is created within the project configuration file, and can be checked-in to version control to lock dependencies.

Package Configuration

jspm extends the package.json spec with some new properties to understand how to treat packages.

Configuration options include the main entry point, module format, files and ignore rules, map config and dependencies (when combined with a registry property).

To provide configuration for existing libraries on GitHub or npm without access to the underlying repo, the jspm registry provides a package.json override service.