Major lint coverage expansion
Biome landed a broad set of new nursery rules across JavaScript, Vue, HTML, Svelte, YAML, and Markdown. Highlights include checks for nested switch statements, unsafe unary minus, nested template literals, inconsistent JSON file reads, arguments.caller/callee, useless assignments, accidental bitwise operators, and several framework-specific rules for Vue and Svelte. Many of these shipped with config/diagnostic wiring and ESLint migration mappings, making them ready for adoption.
Tailwind support got materially better
Tailwind parsing and analysis saw one of the biggest pushes of the week. Biome added noTailwindRestyledComponents and noTailwindLegacyUtilities, expanded noTailwindArbitraryValue with escape hatches, and fixed a long list of parser edge cases around arbitrary variants, nested parentheses, unary operators, leading digits, dashed utilities, CSS-variable shorthands, and @theme syntax. useTailwindSortedClasses was also upgraded to respect Tailwind v4 ordering and read imported project config, so class sorting now reflects real design-system state instead of only built-in defaults.
SCSS, CSS, and selector analysis are much more capable
SCSS moved closer to first-class support: Biome now formats and lints .scss files, treats .module.scss as CSS Modules, and improved parsing/formatting for empty statements, percentage-template bodies, quoted interpolation in unknown at-rules, keyframes, and modern if() branches. CSS selector analysis also got more accurate for nested rules, fixing specificity-related false negatives and improving support for @container and @starting-style patterns.
Vue, Svelte, and HTML workflows improved
Several framework-specific fixes and rules landed together. Vue gained rules for consistent event hyphenation, required props with defaults, and cleaner event/directive formatting; Svelte added checks for unsafe text mustaches and fixed directive parsing, shorthand class:/style: handling, and root-level navigation patterns. HTML also picked up a taxonomy cleanup for useScopedStyles.
CLI, migration, and analysis correctness fixes
The CLI and migration flows got noticeably more polished. inspect config now resolves paths without requiring a key, inspect plugins produces clearer diagnostics, Prettier migration now preserves default semi and singleQuote behavior, and ESLint migration explains more unsupported-rule cases. On the analysis side, Biome fixed type inference for plain arrays, control-flow handling for unlabeled jumps in labeled loops, and exit-code preservation in child-process wrappers.
Other misc changes
- Markdown formatting improved for CJK text and emphasis handling.
noSelfAssign,useLogicalProperties,useImportExtensions,noUselessStringConcat, and several other existing rules were tightened.- GitHub Actions, test infra, generated metadata, lockfiles, and dependency bumps were updated throughout the week.