@canonical/biome-config

This is a Biome configuration that provides a set of default configurations for Biome projects.

Install

1. Install Biome: bun add -d @biomejs/biome
2. Install configuration: bun add -d @canonical/biome-config

Consume

Create biome.json in the root of your project and extend this configuration.

{
  "$schema": "https://biomejs.dev/schemas/1.9.4/schema.json",
  "extends": [
    "@canonical/biome-config"
  ],
  "files": {
    "include": [
      "src",
      "*.json"
    ]
  }
}

Run biome commands as usual. The base configuration will be applied.

Example package.json scripts are provided below.

{
  "scripts": {
    "check": "biome check",
    "format": "biome format",
    "lint": "biome lint"
  }
}

Configuration

This configuration enables the following behavior:

1. Formatting Rules
   1. Two-space indentation
   2. Double-quote strings
2. Organized imports
3. Apply Biome's recommended linting rules by default
4. Disable version control integration: no interaction with Git
   1. Ignores .gitignore: Explicitly includes all files unless they are ignored manually or other files are included explicitly.
   2. Ignores Git add status: No need to stage files before running biome check or biome format.
5. Ignores checking all files in node_modules and dist directories. Please note that if you specify your own ignored files using files.ignore in biome.json, you will override this behavior.

Caveats

Monorepos

Biome does not yet fully support monorepos. Biome and IDE plugins that use it may not work as expected if you are working in a monorepo. As a work-around, Biome suggests including a biome.json at the root of a monorepository, and using overrides to specify any exceptions for sub-packages.

Language support

Biome is still in development and may not support all languages or features. We recommend checking the Biome supported languages list to ensure that your project is supported.

Svelte

We include Svelte-specific overrides because Biome does not yet support "cross-language" lint behavior, which can produce false positives for noUnusedVariables, noUnusedImports, useImportType, and useConst.

These lint overrides are temporary and should be removed once biomejs/biome#8590 is resolved.

We keep these overrides directly in @canonical/biome-config (rather than in a separate Svelte-specific config package) because Biome config extension is not transitive. For additional context, see PR #449.