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| Flag | Default | Description |
|---|---|---|
--line-width |
90 | Maximum line width before splitting |
--use-spaces |
false | Use spaces instead of tabs |
--tab-width |
4 | Number of spaces per indent level |
--write, -w |
false | Write changes to files |
--check |
false | Exit 1 if formatting would change |
- 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