Add knip dead-code scan to check

Wires knip into `bun run check` and removes the three exports it flagged
on the first run: `getSegmentGraphemeWidths` (no callers),
`walkPreparedLines` plus its `InternalLayoutLine` type (only the test
used it, and only as a pass-through to `walkPreparedLinesRaw`), and
`unicodeBidiDataVersion` from the generated bidi data and its generator
(Unicode version is already in the file header).

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

Author: chenglou

DEVELOPMENT.md

@@ -10,7 +10,7 @@ bun install
 
 - `bun start` — stable local page server at <http://localhost:3000>
 - `bun run start:windows` — Windows-friendly fallback without automatic port cleanup
-- `bun run check` — typecheck plus lint
+- `bun run check` — typecheck, lint, and dead-code scan (`knip`)
 - `bun test` — small durable invariant suite
 
 ### Packaging And Release Confidence

bun.lock

@@ -0,0 +1,31 @@
+import type { KnipConfig } from 'knip'
+
+// Test files are in `ignore` so their imports don't count as "usage", flagging exports used only by test files as unused.
+// Tradeoff: dead code & exports within test files won't be detected. See: https://github.com/webpro-nl/knip/issues/1374. This is acceptable
+const config: KnipConfig = {
+  entry: [
+    // Library entry points — match the `exports` field in package.json
+    'src/layout.ts',
+    'src/rich-inline.ts',
+    // Scripts invoked via package.json
+    'scripts/**/*.ts',
+    // Browser pages and demos — each `pages/**/*.ts` is the target of a `<script type="module" src="…">` in a sibling `.html`
+    'pages/**/*.ts',
+  ],
+  ignore: [
+    'src/layout.test.ts', // Exclude tests so their imports don't count as "usage"
+  ],
+  ignoreDependencies: [
+    'tsgolint', // Type-aware checker invoked by `oxlint --type-aware` via oxlint-tsgolint
+  ],
+  ignoreBinaries: [
+    // Used in package.json scripts
+    'lsof',
+  ],
+  // slightly confusing config. We detect dead code just fine
+  // this one's just to silence exported types and values that aren't used elsewhere but that are still used within their file
+  // yelling on unnecessary exports is a bit noisy so we turn it off
+  ignoreExportsUsedInFile: true,
+}
+
+export default config

knip.config.ts

@@ -55,7 +55,7 @@
     "benchmark-check": "bun run scripts/benchmark-check.ts",
     "benchmark-check:safari": "BENCHMARK_CHECK_BROWSER=safari bun run scripts/benchmark-check.ts",
     "build:package": "rm -rf dist && tsc -p tsconfig.build.json",
-    "check": "tsc && oxlint --type-aware src",
+    "check": "tsc && oxlint --type-aware src && knip",
     "corpus-check": "bun run scripts/corpus-check.ts",
     "corpus-check:safari": "CORPUS_CHECK_BROWSER=safari bun run scripts/corpus-check.ts",
     "corpus-font-matrix": "bun run scripts/corpus-font-matrix.ts",
@@ -82,6 +82,7 @@
   },
   "devDependencies": {
     "@types/bun": "latest",
+    "knip": "^6.14.2",
     "marked": "^17.0.5",
     "oxlint": "^1.51.0",
     "oxlint-tsgolint": "^0.15.0",

package.json

@@ -198,8 +198,6 @@ export type GeneratedBidiType =
   | 'WS'
   | 'NSM'
 
-export const unicodeBidiDataVersion = '${payload.unicodeVersion}'
-
 export const latin1BidiTypes: readonly GeneratedBidiType[] = [
 ${latin1Rows},
 ]

scripts/generate-bidi-data.ts

@@ -19,8 +19,6 @@ export type GeneratedBidiType =
   | 'WS'
   | 'NSM'
 
-export const unicodeBidiDataVersion = '17.0.0'
-
 export const latin1BidiTypes: readonly GeneratedBidiType[] = [
   'BN',
   'BN',

src/generated/bidi-data.ts

@@ -30,7 +30,7 @@ let setLocale: LayoutModule['setLocale']
 let countPreparedLines: LineBreakModule['countPreparedLines']
 let measurePreparedLineGeometry: LineBreakModule['measurePreparedLineGeometry']
 let stepPreparedLineGeometry: LineBreakModule['stepPreparedLineGeometry']
-let walkPreparedLines: LineBreakModule['walkPreparedLines']
+let walkPreparedLinesRaw: LineBreakModule['walkPreparedLinesRaw']
 let getSegmentBreakableFitAdvances: MeasurementModule['getSegmentBreakableFitAdvances']
 let prepareRichInline: RichInlineModule['prepareRichInline']
 let layoutNextRichInlineLineRange: RichInlineModule['layoutNextRichInlineLineRange']
@@ -290,7 +290,7 @@ beforeAll(async () => {
     clearCache,
     setLocale,
   } = mod)
-  ;({ countPreparedLines, measurePreparedLineGeometry, stepPreparedLineGeometry, walkPreparedLines } = lineBreakMod)
+  ;({ countPreparedLines, measurePreparedLineGeometry, stepPreparedLineGeometry, walkPreparedLinesRaw } = lineBreakMod)
   ;({ getSegmentBreakableFitAdvances } = measurementMod)
   ;({ prepareRichInline, layoutNextRichInlineLineRange, materializeRichInlineLineRange, measureRichInlineStats, walkRichInlineLineRanges } = richInlineMod)
 })
@@ -1673,7 +1673,7 @@ describe('layout invariants', () => {
       for (let widthIndex = 0; widthIndex < widths.length; widthIndex++) {
         const width = widths[widthIndex]!
         const counted = countPreparedLines(prepared, width)
-        const walked = walkPreparedLines(prepared, width)
+        const walked = walkPreparedLinesRaw(prepared, width)
         expect(counted).toBe(walked)
       }
     }

src/layout.test.ts

@@ -25,14 +25,6 @@ export type PreparedLineBreakData = {
   }[]
 }
 
-export type InternalLayoutLine = {
-  startSegmentIndex: number
-  startGraphemeIndex: number
-  endSegmentIndex: number
-  endGraphemeIndex: number
-  width: number
-}
-
 type InternalLineVisitor = (
   width: number,
   startSegmentIndex: number,
@@ -792,28 +784,6 @@ export function walkPreparedLinesRaw(
   return lineCount
 }
 
-export function walkPreparedLines(
-  prepared: PreparedLineBreakData,
-  maxWidth: number,
-  onLine?: (line: InternalLayoutLine) => void,
-): number {
-  if (onLine === undefined) return walkPreparedLinesRaw(prepared, maxWidth)
-
-  return walkPreparedLinesRaw(
-    prepared,
-    maxWidth,
-    (width, startSegmentIndex, startGraphemeIndex, endSegmentIndex, endGraphemeIndex) => {
-      onLine({
-        startSegmentIndex,
-        startGraphemeIndex,
-        endSegmentIndex,
-        endGraphemeIndex,
-        width,
-      })
-    },
-  )
-}
-
 function stepPreparedChunkLineGeometry(
   prepared: PreparedLineBreakData,
   cursor: LineBreakCursor,

src/line-break.ts

@@ -182,21 +182,6 @@ export function getCorrectedSegmentWidth(seg: string, metrics: SegmentMetrics, e
   return metrics.width - getEmojiCount(seg, metrics) * emojiCorrection
 }
 
-export function getSegmentGraphemeWidths(
-  seg: string,
-  cache: Map<string, SegmentMetrics>,
-  emojiCorrection: number,
-): number[] | null {
-  const widths: number[] = []
-  const graphemeSegmenter = getSharedGraphemeSegmenter()
-  for (const gs of graphemeSegmenter.segment(seg)) {
-    const graphemeMetrics = getSegmentMetrics(gs.segment, cache)
-    widths.push(getCorrectedSegmentWidth(gs.segment, graphemeMetrics, emojiCorrection))
-  }
-
-  return widths.length > 1 ? widths : null
-}
-
 export function getSegmentBreakableFitAdvances(
   seg: string,
   metrics: SegmentMetrics,