Question 1

How do I set up elm-format to format on save in VS Code?

Accepted Answer

Install the Elm Tooling extension, then add "[elm]": {"editor.formatOnSave": true} to your settings.json file. This enables automatic formatting every time you save an Elm file.

Question 2

elm-format or Prettier for Elm code formatting?

Accepted Answer

elm-format is the dedicated, zero-configuration tool for Elm that follows the official style guide, while Prettier requires a plugin and offers more flexibility for multi-language projects. For pure Elm codebases, elm-format is the standard choice.

Question 3

Can I customize elm-format's formatting rules?

Accepted Answer

No, elm-format is opinionated and does not allow any customization of formatting rules—it strictly enforces the Elm Style Guide, so teams must adopt it as-is.

Question 4

What should I do if elm-format isn't working in my editor?

Accepted Answer

First, verify elm-format is installed globally and on your PATH. Then, check the specific plugin's setup steps in the README table, as some editors like Vim or Emacs require additional configuration.

Question 5

How to format only specific files with elm-format?

Accepted Answer

Use the command-line interface: for example, run `elm-format Main.elm` to format a single file, or pass directories like `elm-format src/` to format all Elm files within.

Question 6

Is elm-format compatible with Elm 0.19?

Accepted Answer

Yes, elm-format supports Elm 0.19 and 0.18, but you must run it from the directory containing elm.json or use the --elm-version flag to specify the version explicitly.

Elm Format

What is Elm Format?

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