Credo.Check.Warning.UnusedStringOperation (Credo v1.5.0) View Source

This check has a base priority of high and works with any version of Elixir.

Explanation

The result of a call to the String module's functions has to be used.

While this is correct ...

def salutation(username) do
  username = String.downcase(username)

  "Hi #{username}"
end

... we forgot to save the downcased username in this example:

# This is bad because it does not modify the username variable!

def salutation(username) do
  String.downcase(username)

  "Hi #{username}"
end

Since Elixir variables are immutable, String operations never work on the variable you pass in, but return a new variable which has to be used somehow.

Configuration parameters

There are no specific parameters for this check.

Like with all checks, general params can be applied.

Parameters can be configured via the .credo.exs config file.