Install elm-test and elm-format by running npm install -g elm-test elm-format in a terminal
(Optional) Install elm-review via npm install -g elm-review in a terminal and enable it in your settings
Highlighted Features
Errors and informations when changing code and when saving (Control + S)
Format on save (Control + S) (Make sure you also enable the "Editor: Format on Save" setting for this to work).
Suggests completions and snippets (Control + Space)
Test explorer integration
Additional Features
Lists all references to a type alias, module, custom type or function (Alt + Shift + F12)
Jump to the definition of a type alias, module, custom type or function
Shows type annotations and documentation on hover for type alias, module, custom type or function
Rename a type alias, module, custom type or function (F2)
Browse file by symbols (Control + Shift + O)
Browse workspace by symbols (Control + Shift + R)
Codelenses show how many times you calling a function and if it's exposed or not
Code folding
Type inference
Some more
Extension Settings
This extension contributes the following settings:
elmLS.trace.server: Enable/disable trace logging of client and server communication
elmLS.elmPath: The path to your elm executable.
elmLS.elmReviewPath: The path to your elm-review executable.
elmLS.elmReviewDiagnostics: Configure linting diagnostics from elm-review. Possible values: off, warning, error.
elmLS.elmFormatPath: The path to your elm-format executable.
elmLS.elmTestPath: The path to your elm-test executable.
elmLS.disableElmLSDiagnostics: Disable linting diagnostics from the language server.
elmLS.skipInstallPackageConfirmation: Skip confirmation for the Install Package code action.
elmLS.onlyUpdateDiagnosticsOnSave: Only update compiler diagnostics on save, not on document change.
elmLS.elmTestRunner.showElmTestOutput: Show output of elm-test as terminal task.
Configuration
We used to have a file called elm-tooling.json where you could specifiy "entrypoints". That’s not needed anymore – the language server finds the entrypoints automatically.
If all you had in elm-tooling.json was "entrypoints", you can safely remove that file.
FAQ
Syntax highlighting not working or works only partially?
Make sure the theme you're using supports all the tokens used by the extension (the default VS Code theme currently doesn't support it)
How to get a logfile?
F1 -> Type Output: Focus on Output View -> In the now open panel, use the drop down on the right to choose Elm (your project name)
Most features don't seem to work for me?
This tool needs a valid elm project, please check if you have an elm.json. You can easily initialize your project with elm init. If it still does not work, please try if you get the same behavior with the elm-spa-example.
Why do I need to install elm, elm-test and elm-format?
You will need to install elm and elm-test to get all diagnostics and elm-format for formatting. If your setup fails to find the global installations of those, you can use the settings panel in VSCode to set the paths to the executable manually. Alternatively you can also just install these to your local npm package.json.
I don't like the inserted lines for "X references" (CodeLenses)
You can configure VSCode to not show them, just look for "Editor: Code Lens" in your settings.
