Elixir: When to use .ex and when .exs files

Question

Elixir\'s documentation states that

In addition to the Elixir file extension .ex, Elixir also supports .exs files for scripting. Elixir treats both

Answer 1

.ex is for compiled code, .exs is for interpreted code.

ExUnit tests, for example, are in .exs files so that you don't have to recompile every time you make a change to your tests. If you're writing scripts or tests, use .exs files. Otherwise, just use .ex files and compile your code.

As far as pros/cons, interpretation will take longer to execute (as elixir has to parse, tokenize, etc.), but doesn't require compilation to run. That's pretty much it - if the flexibility of running scripts is more important than optimized execution time, use .exs. Most of the time, you'll use .ex.