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Optimus Prime is a Transformer (okay, it’s an instance of a babel-jest transformer).

About This Repository

This repository is a part of the Byte-Sized JavaScript Screencasts.

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            »»  bytesized.tv  ««

Byte-Sized What?!

Byte-Sized JavaScript.

It is a compilation of short (around ten minutes) monthly screencasts about JavaScript and related technologies.

About Optimus Prime

Optimus Prime is a babel-jest transformer.

I needed to create one, because I wanted to run a set of babel transformations in jest, and then realized that jest was swallowing the transform plugins that I specified in the .babelrc file.

It took a while for me to figure things out. And then as any good open-source citizen would do, [I patched jest, and created a Pull Request][jest-patch]; however, the pull requrest got rejected, suggesting that a better way would be to create a transformer to do this task instead.

And thus, Optimus Prime was born :).


Using npm:

npm install optimusprime

Using yarn:

yarn add optimusprime


Create an OptimusPrime.js in our project root:

// ./OptimusPrime.js
module.exports = require( 'optimusprime' );

Configure jest to use Optimus Prime:

// package.json
    "transformIgnorePatterns": [
    "transform": {
      "^.+\\.(js|jsx)$": "<rootDir>/OptimusPrime.js"


Optimus Prime is a jest transformer, so obviously you’ll need jest.

You will also need the current version of Node.JS with all the bells and whistles — You can install it from nodejs.org.

Note that Optimus Prime will probably work with older Node.JS versions too (unless it’s archaic like v4.x or v5.x); however, it’s being tested and developed only with the current Node.JS version at the moment.

If you have problem using Optimus Prime in an older Node.JS runtime, file an issue, and we’ll see what we can do about it ;).

Package Scripts

None at the moment.

Important Files and Folders

  • ./lib/*: The source files live here.
  • ./CHANGELOG.md: A log of what has been done since the last version.
  • ./CODE_OF_CONDUCT.md: Tells the collaborators to be nice to each other.
  • ./README.md: This very file.
  • ./.eslintrc: Used for development; configures [eslint][eslint].
  • .travis.yml: Used for CI; configures [Travis][travis].

Wanna Help?

Any help is more than appreciated.

If you want to contribute to the source code, fork this repository and create a pull request.

In lieu of a formal style guide, take care to maintain the existing coding style.

Also, don’t forget to add unit tests for any new or changed functionality.

If you want to report a bug; or share a comment or suggestion, file an issue.

I’ve Found a Bug; I Have an Idea

[For bug reports and suggestions, please file an issue][issues].

Contact Information


MIT-licensed. — See the license file for details.

Code of Conduct

We are committed to making participation in this project a harassment-free experience for everyone, regardless of the level of experience, gender, gender identity and expression, sexual orientation, disability, personal appearance, body size, race, ethnicity, age, religion, or nationality.

See the code of conduct for details.


npm i optimusprime

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