Adopting Elixir

Typespecs and Dialyxir

Functional languages depend heavily on types to determine how functions interact with one another. You can dramatically improve a function’s declaration of intent with typespecs. A typespec annotates the expected input and outputs of a function. Typespecs aren’t required, but they may be worthwhile because they require the developer to explicitly state what a function accepts and what it returns.

Since many bugs creep in at system boundaries such as function interfaces, declaring and enforcing types when you make your function definitions lets you find bugs and improve documentation for your programs. Typespecs are a consistent and repeatable way to document your system and decrease bugs. They’re especially useful for ...