jj fix allows you to run a "fix tool" like a formatter, linter, etc., against every commit in a branch all at once.

Protocol

• The tool must accept the original source code on standard input
• The tool must output the fixed source code on standard output
• The tool may output human-readable information on standard error, this will be displayed to the user
• The replacement variable $path may be used to pass the file name to the fix tool.
• The tool is executed with the workspace root as its working directory.

Tools

Biome

Biome is a JavaScript formatter and linter.

[fix.tools.biome]
command = ["biome", "check", "--stdin-file-path=$path", "--write"]
# run with npx:
#   command = ["npx", "@biomejs/biome", "check", "--stdin-file-path=$path", "--write"]
# run from node_modules:
#   command = ["$root/node_modules/.bin/biome", "check", "--stdin-file-path=$path", "--write"]

patterns = [
    "glob:'**/*.js'",
    "glob:'**/*.jsx'",
    "glob:'**/*.ts'",
    "glob:'**/*.tsx'",
    "glob:'**/*.json'",
]

CSharpier

CSharpier is an opinionated formatter for C# files.

[fix.tools.csharpier]
command = ["dotnet", "csharpier", "--write-stdout"]
patterns = ["root-glob:'**/*.cs'"]

fish_indent

fish_indent is the official indenter and prettifier shipped with fish shell.

[fix.tools.fish_indent]
command = ["fish_indent"]
patterns = ["glob:'**/*.fish'"]

Gofmt, gofumpt

The trivial config works for many Go ecosystem tools.

[fix.tools.gofmt]
patterns = ["glob:'**/*.go'"]
command = ["gofmt"]

# [fix.tools.gofumpt]
# patterns = ["glob:'**/*.go'"]
# command = ["gofumpt"]

ktfmt

ktfmt is a Kotlin formatter, based on google-java-format.

[fix.tools.ktfmt]
command = ["ktfmt", "--kotlinlang-style", "--stdin-name=$path", "-"]
patterns = ["glob:'**/*.kt'"]

# --meta-style        Use 2-space block indenting 
# --google-style      Google internal style (2 spaces)
# --kotlinlang-style  Kotlin language guidelines style (4 spaces)

Prettier

Prettier is a JavaScript formatter. It supports related languages as well, such as HTML, CSS, and Markdown.

[fix.tools.prettier]
command = ["prettier", "--stdin-filepath", "$path"]
# run with npx:
#   command = ["npx", "prettier", "--stdin-filepath", "$path"]
# run from node_modules:
#   command = ["$root/node_modules/.bin/prettier", "--stdin-filepath", "$path"]
patterns = [
    "glob:'**/*.js'",
    "glob:'**/*.jsx'",
    "glob:'**/*.ts'",
    "glob:'**/*.tsx'",
    "glob:'**/*.json'",
    "glob:'**/*.html'",
    "glob:'**/*.md'",
    "glob:'**/*.css'",
]

Rubocop

Rubocop is a formatter and linter for Ruby files.

[fix.tools.rubocop]
command = ["rubocop", "--config", ".rubocop.yml", "--autocorrect", "--stdin", "$path", "--stderr"]
patterns = ["glob:'**/*.rb'"]

ruff

Ruff is a linter and formatter for Python files

[fix.tools.ruff]
command = ["ruff", "-", "--stdin-filename=$path"]
patterns = ["glob:'**/*.py'"]

Rustfmt

Rustfmt is a formatter for Rust files.

[fix.tools.rustfmt]
command = ["rustfmt", "--emit", "stdout", "--edition", "2024"]
patterns = ["glob:'**/*.rs'"]

shfmt

shfmt is a formatter for bash/zsh scripts.

[fix.tools.shfmt]
command = ["shfmt", "--filename=$path"]
patterns = ["glob:'**/*.sh'"]

Terraform

Terraform is an Infrastructure-as-Code tool.

[fix.tools.terraform]
command = ["terraform", "fmt", "-"]
patterns = ["glob:'**/*.tf'"]

yamlfmt

yamlfmt formats YAML files.

[fix.tools.yamlfmt]
command = ["yamlfmt", "-in"]
patterns = ["glob:'**/*.yml'", "glob:'**/*.yaml'"]