Formatting

bun fmt formats JavaScript, TypeScript, JSX, JSON, CSS, Markdown, YAML, TOML and more with oxfmt, a Prettier-compatible formatter.

bun fmt

With no paths, oxfmt formats the working directory. Pass files, directories or globs to format only those. A path starting with ! excludes files.

bun fmt src 'test/**/*.ts' '!test/fixtures'

Check formatting in CI

--check writes nothing and exits with code 1 when a file is not formatted. --list-different prints those files.

bun fmt --check

How oxfmt is installed

oxfmt is not part of the bun binary. The first bun fmt downloads a pinned version with bun x and caches it. bun fmt uses node_modules/.bin/oxfmt instead when the project installs oxfmt itself.

Changed files and workspaces

# files changed since a git ref, plus staged, unstaged and untracked files
bun fmt --since=main

# every workspace package, or the ones matching a filter
bun fmt --workspaces
bun fmt --filter 'packages/*'

Configure

bun fmt reads .oxfmtrc.json the same way oxfmt does. See the oxfmt configuration reference.

{
  "printWidth": 120,
  "semi": true,
  "ignorePatterns": ["dist/**"]
}

Project defaults go in the [fmt] section of bunfig.toml.

[fmt]
# oxfmt configuration file
config = ".oxfmtrc.json"
# paths formatted when none are given
paths = ["src", "test"]
# glob patterns to skip
ignore = ["dist/**"]
# more oxfmt arguments
args = []
# oxfmt version to download
version = "0.72.0"

Flags

Every other flag goes to oxfmt.

If package.json has a fmt script, bun fmt runs that script. Inside the script, bun fmt is the command.

To lint code, use bun lint.