prettier-plugin-elm

0.12.0 verified Sat Apr 25 auth: no javascript

Adds Elm language support to Prettier by wrapping elm-format. Version 0.12.0 (2025-09-21) requires Node >=18.20.6 and uses elm-format 0.8.8. Works with Prettier v2 (global) or v3 (local with explicit plugin config). Formats .elm files and Elm code blocks inside Markdown documents, with support for . Key differentiators: integrates elm-format directly into the Prettier ecosystem, handles both standalone files and embedded code blocks. Vendors elm-format internally, reducing version conflicts. Designed for Elm 0.19; older plugin versions support Elm 0.18. Maintained by giCentre, with TypeScript source code.

Common errors

error Error: Cannot find module 'prettier-plugin-elm' ↓

cause Plugin not installed or not in node_modules.

fix

Run 'npm install --save-dev prettier-plugin-elm' (local) or 'npm install --global prettier-plugin-elm' (global).

error Error: [prettier-plugin-elm] Could not find elm-format. ↓

cause The vendored elm-format binary is missing or corrupted.

fix

Reinstall the plugin: npm install prettier-plugin-elm. Ensure network access for binary download.

error Error: [prettier-plugin-elm] elm-format timed out ↓

cause Elm file formatting took longer than expected; possibly large file or infinite loop.

fix

Increase timeout via PR or reduce file size. Check elm-format version compatibility.

error Error: Plugin loaded but no parser found for '.elm' ↓

cause Prettier v3 without explicit plugin listing.

fix

Add "plugins": ["prettier-plugin-elm"] to .prettierrc.

Warnings

breaking Minimum Node.js version increased to 18.20.6 in v0.12.0 ↓

fix Upgrade Node.js to v18.20.6 or later.

breaking Node.js v14 minimum required in v0.9.0, v12 in v0.8.0, v8 dropped in v0.6.0, v6 in v0.5.0 ↓

fix Use older plugin version if running on legacy Node.js, or upgrade Node.

gotcha Prettier v3 does not support automatic plugin discovery; manual plugin listing is required. ↓

fix Add "plugins": ["prettier-plugin-elm"] to .prettierrc or Prettier config file.

gotcha elm-format is vendored; installing separate elm-format globally may cause version mismatches. ↓

fix Do not install elm-format separately; the plugin uses its own bundled version.

deprecated Plugin assumes Elm 0.19; for Elm 0.18 use prettier-plugin-elm@0.3. ↓

fix Use version 0.3.x for Elm 0.18 compatibility.

Install

npm install prettier-plugin-elm

yarn add prettier-plugin-elm

pnpm add prettier-plugin-elm

Imports

default

wrong

import prettierPluginElm from 'prettier-plugin-elm'; // ESM import will fail – plugin is CommonJS

correct

const prettierPluginElm = require('prettier-plugin-elm');

The plugin does not export an ES module; use CommonJS require() or use Prettier's config resolution (plugins array).

prettierPluginElm in .prettierrc
wrong
```
Using plugins array without specifying package name or wrong casing
```
correct
```
{
  "plugins": ["prettier-plugin-elm"]
}
```
With Prettier v3, you must list the plugin explicitly in the config file; global install with v2 auto-detects.
CLI usage
wrong
```
Calling prettier with no plugin installed or using older elm-format version inline.
```
correct
```
prettier --write '**/*.elm'
```
Run prettier directly on .elm files; the plugin is loaded automatically when installed globally (v2) or via config (v3).

Quickstart

Global installation with Prettier v2 and formatting a single file; also shows local config for Prettier v3.

// Install Prettier v2 globally and the plugin
// npm install --global prettier@2 prettier-plugin-elm
//
// Now format an Elm file:
// prettier --write Main.elm

// Or for local project with Prettier v3:
// npm install --save-dev prettier prettier-plugin-elm
// Then in .prettierrc:
{
  "plugins": ["prettier-plugin-elm"]
}
// Run: npx prettier --write src/**/*.elm