Interview with Flarnie Marchan

One of the women at the heart of React

Rachel Nabors
Dec 12, 2019 · 3 min read

Flarnie was a software engineer on React Core at Facebook from early in 2017 through late 2018. In this interview, she talks a bit about what it was like to work on React Core and how you too can get started contributing to opensource! You can find her on Twitter as @ProvablyFlarnie.

Any of us can contribute to open source projects.

What do you do now?

Using React to build web applications is what I did before and since my time on the React Core team, and I try to build things that will help people.

What’s your workspace like?

A coffee shop with strong, free wifi, delicious cookies, plenty of outlets, and enough space for me to sit alone. I use a Macbook, and sometimes a Microsoft ergonomic keyboard. If I could find a coffee shop with standing desks and monitors, that would be heaven.

What did you do when you worked on React Core?

Improving developer experience by rewording and fixing warning messages was my first contribution to the React core codebase. Fixing or improving warning and error messages is still a good way to get started contributing to open source projects, and has high pay-off by improving the developer experience.

Leading the 15.6.0 release was my other early contribution — I only wrote minor fixes and changes to the code itself, but there were many non-coding tasks required to prepare the release branch, change log, umbrella issue, and blog post to get the release out. I did some of this type of work to help get the 16.0 release out, but for that release there was enough work that the whole React team was helping push the release out. I also was starting to shift my focus to get back to coding more.

Given the exciting and innovative development of React’s experimental concurrent mode, I decided to focus on that during most of 2018. The rewrite of the reconciler code, aka Fiber, had put the code in place to support concurrent mode, but there were still some things to fix to get it production ready. I wrote a new iteration of the scheduler module used for React concurrent mode, and collaborated on other changes to code that enabled testing concurrent mode in real React apps. I then coordinated the first internal tests of concurrent mode at Facebook.

Do you still work with React?

I am a React developer, but have not lately been working on the core React codebase. Ideally engineers can use React without needing to understand it’s implementation, but I have found it comes in handy fairly often.

What was it like working with React?

Working on React and other infrastructure codebases reminded me of all the pain points that React paves over for us. There is a lot of imperative code, and tricks to optimize performance. Working with React and other infrastructure projects was also when I found my self-taught computer science knowledge to be most useful.

How would you recommend someone get started with contributing to Opensource?

I am a regular software engineer, just like many of you. Any of us can contribute to open source projects. If you’re interested in open source, here is one trick to try: Contribute to a project where you know the maintainer in real life. If you have coworkers or friends who are doing open source projects, even if the project is not widely recognized yet, that’s still a great place to start. It’s easier to get your pull request merged if you can talk face to face. From that you will gain skills and confidence to open pull requests for projects whose maintainers you’ve never met.

I’d also like to acknowledge that I benefited from many layers of privilege on my journey, and I commit to share my privilege to open doors for others to gain opportunities in the tech industry. I hope we can all work together on this front.


This interview appeared in a condensed format in the 2019 Women at the Heart of React Zine. It is part of a series of interviews with women who contribute to React Core and organize the React Community. Portrait by Xyra Brittney.

React Community Stories

React and React Native community members around the world are doing incredible things with their communities, with open source, and with each other. Here we highlight and celebrate these amazing folks and share their stories with the world!

Rachel Nabors

Written by

React Core Team @ Facebook. Long ago made award-winning comics for teenage girls. Wrote a book on UI animation: bkaprt.com/animationatwork

React Community Stories

React and React Native community members around the world are doing incredible things with their communities, with open source, and with each other. Here we highlight and celebrate these amazing folks and share their stories with the world!

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