Datastar attribute formatter — reflows Datastar data-* attributes and formats Datastar expressions in HTML, JSX, and TSX files.

cargo install --git https://github.com/hyperpuncher/dsfmt

# Format a file (prints to stdout)
dsfmt src/components/slider.tsx

# Write changes back
dsfmt --write src/components/slider.tsx

# Format all supported files in a directory
dsfmt --write src/

# Check if files are formatted (exit code 1 if changes needed)
dsfmt --check src/

# Read from stdin
cat file.html | dsfmt

• Detects Datastar attributes with tree-sitter-datastar
• Ignores generic non-Datastar attributes like data-testid
• Splits elements with 2+ Datastar attributes across multiple lines when they don't fit
• Formats inline Datastar expressions with OXC where possible
• Trims outer whitespace in Datastar attribute values
• Splits multi-statement template literal expressions (data-effect={\a=1; b=2`}`)
• Splits object/array values in quoted attributes (data-signals="{a:1, b:2}")
• Normalizes top-level , to ; in template statements
• Preserves non-Datastar markup/source text byte-for-byte where possible

HTML, JSX, TSX, Templ, HEEx, Blade