Using modules in Elm

This post is adapted from my book, [Practical Elm for Busy Developers.]

As your Elm code base grows, you will want to start taking advantage of modules to split the code into manageable smaller parts.

In Elm, files and modules have a one-to-one correspondence. If you want to break out a piece of code into a separate file, you have to organise it as a module in that file.

The general approach I would suggest is to start your project with a single file (Main.elm), and keep adding to it until y...