REX is a tool that takes your JavaScript source files and serves a bundle that you deploy to clients.
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REX Build Status

REX is a tool that takes your JavaScript source files and serves a bundle that you deploy to clients. It is a standalone version of the packager included with React Native. If you need a JavaScript packager without the rest of React Native, this is your tool.


Install REX from npm:

npm i @exponent/rex

You can start the packager by running node_modules/@exponent/rex/src/ I realize this isn't ideal. It's just how things work right now 😅


We welcome collaborators, especially if you're interested in building tools that keep this repository in sync with the upstream React Native project.

Tasks we need help on:

  • Writing a little Node bot that is pinged whenever there is a commit to the upstream React Native repo
  • Checking if that commit touches any of the files or directories of interest to REX
    • This would be the jestSupport and packager directories for now
  • Create a new commit that pulls over just the relevant changes
    • We don't care about non-packager code
    • Preserve details about the original author
    • Include a link to the original PR and commit in case a person needs to look it over
  • Automatically submit a PR with the commit
  • Automatically merge the PR if Travis CI tests pass
  • If tests fail we need a way for a person to take over a PR
    • Document that process for collaborators

Please open up an issue if you start working on one of these so that we can efficiently work together.


The name REX comes from React EXpress, deliverer of packages.


The packager is derived from the React Native project. It's license and patent grants are included in this repository. There is also a BSD license for code that is not from React Native.