Foreword
You might not be able to tell by using it but the frontend of twitter.com is incredibly
complex. Back in 2011, this complexity was growing at an exponential rate as we
added features. Our client- side code was essentially a proto MVC application, built
long before frameworks such as Backbone.js and Ember.js had become popular, so
was far from spaghetti code but, nevertheless, the multitude of relationships between
these models, views, and controllers was almost impossible for one engineer to fully
understand.
In order to make a change in one part of the code base, our engineers needed
to understand every reference made to that piece of code in the application. If
JavaScript was statically typed, we’d have been able to rely on that to help us, as
it was all too easy to make a trivial update to one part of the application but later,
much, much later, we discovered that this had broken a seemingly unrelated part
of the code base. I’m sure you’ve been there, done that, and lost your mind more
than once.
This was the situation that inspired us to create Flight.js. We wanted to be able to
create the complex client-side interactions that power great web applications while
retaining the simplicity of our code. Flight.js has massively improved the testability,
robustness, and maintainability of many of our web applications and now, with the
help of this book, we think you can, maybe, hopefully, save a little bit of sanity too.
Dan Webb
Web Core Engineering Manager at Twitter
