Biome

The Biome checker reports lint, format, and import-sorting problems using Biome and your project's biome.json.

Set up

1. Install Biome (version 2.4.12 or later):

   pnpm

   pnpm add -D @biomejs/biome

   npm

   npm install -D @biomejs/biome

   yarn

   yarn add -D @biomejs/biome

   bun

   bun add -d @biomejs/biome

2. Enable the checker:

   checker({
     biome: true,
   })

With biome: true, dev mode runs biome lint and build mode runs biome check. Both run from the Vite root.

Choose the command and flags

Set command to one of 'lint', 'check', 'format', or 'ci', and flags to pass Biome CLI flags. These apply in both modes:

checker({
  biome: {
    command: 'check',
    flags: '--diagnostic-level=warn',
  },
})

To use different values per mode, set dev or build. They take precedence over the top-level command and flags:

checker({
  biome: {
    dev: {
      command: 'lint',
    },
    build: {
      command: 'ci',
      flags: '--reporter=github',
    },
  },
})

In dev mode, the checker reads Biome's JSON output, so it ignores --reporter and --reporter-file and prints a warning. Use build.flags to set a reporter for build mode.

Don't pass --write or --fix; Biome would modify your files while the dev server or build runs.

How dev mode works

When the dev server starts, the checker runs Biome on the whole project. When a file changes, it runs Biome on the changed files only. When biome.json changes, it runs on the whole project again.

To watch fewer files, set watchPath:

checker({
  biome: {
    watchPath: './src',
  },
})

Options

Option	Type	Default	Description
command	'lint' | 'check' | 'format' | 'ci'	'lint' in dev, 'check' in build	Biome command to run.
flags	string	''	CLI flags for the command.
watchPath	string | string[]	The Vite root	Paths to watch in dev mode, relative to the root.
dev.command	'lint' | 'check' | 'format' | 'ci'	command	Biome command to run in dev mode.
dev.flags	string	flags	CLI flags for the command in dev mode.
dev.logLevel	('error' | 'warning' | 'info')[]	['error', 'warning', 'info']	Diagnostic levels to report in dev mode.
dev.debounceMs	number	300	Time in milliseconds to wait after a change before linting. Changes within this window are linted together.
build.command	'lint' | 'check' | 'format' | 'ci'	command	Biome command to run in build mode.
build.flags	string	flags	CLI flags for the command in build mode.