# Linting & Formatting

Catch bugs and style issues automatically — before review, before CI, ideally before saving.

## Tools by Language

| Language | Recommended | Alternatives |
|---|---|---|
| Python | `ruff` | flake8 + isort + black |
| JavaScript/TS | `biome` | eslint + prettier |
| Go | `gofmt`, `golangci-lint` | staticcheck |
| C++ | `clang-tidy`, `clang-format` | cppcheck |

## Python — `ruff`

Replaces flake8, isort, and black in one tool. Extremely fast.

```bash
ruff check .          # lint
ruff check --fix .    # lint + auto-fix
ruff format .         # format (replaces black)
```

Configure in `pyproject.toml`:

```toml
[tool.ruff]
line-length = 100
target-version = "py312"

[tool.ruff.lint]
select = ["E", "F", "I", "UP"]
```

## JavaScript — `biome`

Single tool for lint + format, no config needed to start.

```bash
biome check .         # lint + format check
biome check --write . # auto-fix
```

## Go

`gofmt` is part of the toolchain — just run it.

```bash
gofmt -w .
golangci-lint run     # broader lint suite
```

## Tips

- Run on save in your editor (not just in CI)
- Auto-fix on commit via a pre-commit hook or `invoke lint --fix`
- Format is non-negotiable; lint violations should be treated as errors in CI