Episode 329

JSJ 325: Practical functional programming in JavaScript and languages like Elm with Jeremy Fairbank


August 7th, 2018

53 mins 47 secs

Your Hosts

About this Episode


  • Aimee Knight
  • Joe Eames
  • AJ ONeal

Special Guests: Jeremy Fairbank

In this episode, the JavaScript Jabber panel talks to Jeremy Fairbank about his talk Practical Functional Programming. Jeremy is a remote software developer and consultant for Test Double. They talk about what Test Double is and what they do there and the 6 things he touched on in his talk, such as hard to follow code, function composition, and mutable vs immutable data. They also touch on the theory of unit testing, if functional programming is the solution, and more!

In particular, we dive pretty deep on:

  • Jeremy intro
  • Works for Test Double
  • What he means by “remote”
  • What is Test Double?
  • They believe software is broken and they are there to fix it
  • His talk - Practical Functional Programming
  • The 6 things he talked about in his talk
  • Practical aspects that any software engineer is going to deal with
  • Purity and the side effects of programming in general
  • Hard to follow code
  • Imperative VS declarative code
  • Code breaking unexpectedly
  • Mutable data VS immutable data
  • The idea of too much code
  • Combining multiple functions together to make more complex functions
  • Function composition
  • Elm, Elixir, and F#
  • Pipe operator
  • Scary to refactor code
  • Static types
  • The idea of null
  • The theory of unit testing
  • Is functional programming the solution?
  • His approach from the talk
  • And much, much more!