1.6.15 • Public • Published

reg - Native ESM Package Management

reg is a package manager for native ES Modules. It's built to enable dependency management for Universal JavaScript (JavaScript that can run in the Browser and in Node.js w/o a compiler).

This library is highly experimental and still likely to break without notice. DO NOT USE THIS IN PRODUCTION.

Supporting Universal JavaScript is quite difficult as the Browser's module system has a very unique set of constraints. In order to build effective dependency management on-par with the features you'd expect from npm the approach reg takes is radically different.

reg statically links the dependency tree by hash reference, re-writing the import statements of the output files (this is the only alteration to your source file reg does, it is not a compiler). A package registry is then just a namespace that maps users, package names, and versions to specific package hashes. You can then directly import the resulting package references in a Browser or in Node.js with a special loader.

Note: since this is built for Universal JavaScript, you cannot use any of the Node.js standard library or any packages from npm since none of this is available in Browsers without a compiler.


reg input-file.js

This command takes an input file, statically links the dependency tree, stages it in a local cache and executes the input file.

reg @mikeal/test/1.0.0

The same command can also take a package reference from the registry.

reg publish <filename> <name> <semver>

Publish an input file to a package to the registry.

    filename  Filename of script to run. Example `reg input.js`
    semver    Package version number.

      --help     Show help
      --version  Show version number
      --token    GitHub personal access token
                 Defaults to process.env.GHTOKEN || process.env.GITHUB_TOKEN

Note that this command requires a GitHub Token that only needs enough permissions to validate the user, no write or read access to any of your repositories are required.

All package names must be proceeded by the user's GitHub username. There are currently no top level packages.

Developer CLI

There are several more commands that have been useful while developin this software. They may eventually be removed from the public API.

Run a local script file in reg

  cli.js stage <filename>                   Run the linker and stage the tree in
                                            local cache
  cli.js linker <filename>                  Run the static linker
  cli.js info <name>                        Get info for named alias
  cli.js cat <name>                         Print the file data for the named
  cli.js pkg-info <cid|name>                Get package information

Data Model

reg implements a data model for its package data that is similar to git in many ways. The highlights of this data structure are:

  • Optimized for offline, sync, and decentralization (just like git!)
  • A module is only a single file (the Browser requires this) with the dependency tree attached.
  • Every module gets a unique hash (like a git commit) which means cache de-duplication works across differing module names and version.
  • Every file is chunked with an algorithm called Rabin which creates good block boundaries for diffing (this is what rsync uses). This gives us sub-file de-duplication in cache which is especially useful for de-duplicating file parts between versions.

This data structure also enables some important HTTP/2 features we need in order to be competitive with bundle performance.

  • HTTP/2 Push for all of the dependencies required by a single import.
  • If an old e-tag is presented for a module, reg can diff the two dependency trees and use HTTP/2 Push of only the assets that have changed.

For a more detailed look at the data structure you can read the schema.

Some visual examples follow:










npm i reg

DownloadsWeekly Downloads





(Apache-2.0 AND MIT)

Unpacked Size

26.4 kB

Total Files


Last publish


  • mikeal
  • pvorb