Add elm-format (#100)

* feat: add elm-format

* fix: master => main

* Update elm-format.bash

Co-authored-by: Radon Rosborough <radon.neon@gmail.com>

CHANGELOG.md

@@ -17,10 +17,12 @@ The format is based on [Keep a Changelog].
   (e.g. scalafmt), do not erase the buffer ([#116]).
 
 ### Formatters
+* [elm-format](https://github.com/avh4/elm-format) for Elm ([#100]).
 * [bean-format](https://github.com/beancount/beancount) for Beancount
   ([#101]).
 * [stylua](https://github.com/JohnnyMorganz/StyLua) for Lua ([#105]).
 
+[#100]: https://github.com/radian-software/apheleia/pull/100
 [#101]: https://github.com/radian-software/apheleia/pull/101
 [#105]: https://github.com/radian-software/apheleia/pull/105
 [#109]: https://github.com/radian-software/apheleia/issues/109

apheleia.el

@@ -923,6 +923,7 @@ being run, for diagnostic purposes."
     (brittany . ("brittany"))
     (clang-format . ("clang-format"))
     (dart-format . ("dart" "format"))
+    (elm-format . ("elm-format" "--yes" "--stdin"))
     (fish-indent . ("fish_indent"))
     (gofmt . ("gofmt"))
     (google-java-format . ("google-java-format" "-"))
@@ -1056,6 +1057,7 @@ function: %s" command)))
     (css-mode . prettier)
     (dart-mode . dart-format)
     (elixir-mode . mix-format)
+    (elm-mode . elm-format)
     (fish-mode . fish-indent)
     (go-mode . gofmt)
     (haskell-mode . brittany)

test/formatters/installers/elm-format.bash

@@ -0,0 +1 @@
+npm install -g elm-format

test/formatters/samplecode/elm-format/in.elm

@@ -0,0 +1,2 @@
+import Html exposing (text)
+main = text "Hello!"

test/formatters/samplecode/elm-format/out.elm

@@ -0,0 +1,7 @@
+module Main exposing (main)
+
+import Html exposing (text)
+
+
+main =
+    text "Hello!"