Biome rules

Rule	Catches	Enable via
noReExportAll	export * from	@house-rules/rules/biome
noExcessiveLinesPerFile	Files over 300 lines (warn)	@house-rules/rules/biome
noNonNullAssertion	! non-null assertions	@house-rules/rules/biome
useFilenamingConvention	Files not kebab-case or export	@house-rules/rules/biome
Formatter	indentWidth 2, lineWidth 100, indentStyle space	@house-rules/rules/biome

Biome preset

From packages/rules/docs/biome.md.

Import path: @house-rules/rules/biome

It is drunk-cat-stack’s biome.json without the files block: formatter on (spaces, indent 2, line width 100), assist off, and the linter with preset: "none" plus four rules.

Rule	Level
performance/noReExportAll	error
style/noNonNullAssertion	error
style/useFilenamingConvention (kebab-case or export)	error
style/noExcessiveLinesPerFile (300 lines, blank lines counted)	warn

biome.json

{
  "$schema": "https://biomejs.dev/schemas/2.5.14/schema.json",
  "extends": ["@house-rules/rules/biome"],
  "files": {
    "includes": ["**", "!!node_modules", "!!dist", "!!coverage", "!!generated", "!!.agent_sources"]
  }
}

Biome resolves the specifier through this package’s exports map. The preset file is biome/preset.json, not biome.json, because Biome treats a nested file named biome.json as a second root config.

Why files stays in the consumer

Biome does not merge files.includes from an extended config with the consumer’s. When the consumer sets files.includes, the preset’s list is dropped. A consumer that added one exclude would silently lose the rest. So the preset leaves files out, and each repository lists its own excludes. Globs in the consumer’s list resolve against the consumer’s root.

Tested against

Biome 2.5.14. A test extends the preset from a symlinked install, checks a clean file passes, and checks that export *, a non-null assertion and a PascalCase file name each fail by rule name.

All rules