Communications of the ACM

practice

ONE OF THE long-standing ironies of user-friendly JavaScript frontends is that building them typically involved trudging through the DOM (Document Object Model), hardly known for its friendliness to developers. But now developers have a way to avoid directly interacting with the DOM, thanks to Facebook’s decision to open source its React library for the construction of user interface components.

React essentially manages to abstract away the
DOM, thus simplifying the programming model while
also—in a somewhat surprising turn—improving
performance. The key to both advances
is that components built from stan-
dard JavaScript objects serve as the fun-
damental building blocks for React’s
internal framework, thus allowing for
greatly simplified composability. Once
developers manage to get comfortable
with building front ends in this way,
they typically find they can more readi-
ly see what is going on while also enjoy-
ing greater flexibility in terms of how
they structure and display data.
All of which caused us to wonder
about what led to the creation of React in
the first place and what some of its most
important guiding principles were. For-
tunately for us, Pete Hunt, who at the
time was an engineering manager at
Instagram as well as one of the more
prominent members of Facebook’s
React core team, is willing to shed some
light on React’s beginnings. Hunt has
since gone on to cofound Smyte, a San
Francisco startup focused on security
for marketplaces and social networks.

Also helping to tell the story is Paul O’Shannessy, one of the first engineers at Facebook to be dedicated to React full time. He came to that role from Mozilla, where he had previously worked on the Firefox front end.

The job of asking the probing questions that drive the discussion forward falls to Dave Smith and Terry Coatta. Smith is an engineering director at HireVue, a Salt Lake City company focused on team-building software, where he has had an opportunity to make extensive use of both Angular and React. Coatta is the CTO of Marine Learning Systems, where he is building a learning management system targeted at the maritime industry. He is also a member of the acmqueue editorial board.

DAVE SMITH: What is it exactly that led to the creation of React?

PETE HUNT: Of all the Web apps at Facebook, one of the most complex is what we use to create ads and manage ad accounts. One of the biggest problems is keeping the UI (user interface) in sync with both the business logic and the state of the application. Tradi-