refactor(kiwi): move FIG container helpers

packages/core/src/kiwi/fig/container/kiwi.ts

@@ -1,75 +1,7 @@
-import { deflateSync, inflateSync } from 'fflate'
+export {
-
+  buildFigKiwi,
-export const FIG_KIWI_DEFAULT_VERSION = 101
+  decompressFigKiwiData,
-
+  decompressFigKiwiDataAsync,
-export function parseFigKiwiChunks(binary: Uint8Array): Uint8Array[] | null {
+  FIG_KIWI_DEFAULT_VERSION,
-  const header = new TextDecoder().decode(binary.slice(0, 8))
+  parseFigKiwiChunks
-  if (header !== 'fig-kiwi') return null
+} from '@open-pencil/kiwi/fig/container'
-
-  const view = new DataView(binary.buffer, binary.byteOffset, binary.byteLength)
-  let offset = 12
-
-  const chunks: Uint8Array[] = []
-  while (offset < binary.length) {
-    const chunkLen = view.getUint32(offset, true)
-    offset += 4
-    chunks.push(binary.slice(offset, offset + chunkLen))
-    offset += chunkLen
-  }
-  return chunks.length >= 2 ? chunks : null
-}
-
-export async function decompressFigKiwiDataAsync(compressed: Uint8Array): Promise<Uint8Array> {
-  if (
-    compressed.length >= 4 &&
-    compressed[0] === 0x28 &&
-    compressed[1] === 0xb5 &&
-    compressed[2] === 0x2f &&
-    compressed[3] === 0xfd
-  ) {
-    const { decompress } = await import('fzstd')
-    return decompress(compressed)
-  }
-  try {
-    return inflateSync(compressed)
-  } catch {
-    const { decompress } = await import('fzstd')
-    return decompress(compressed)
-  }
-}
-
-export function buildFigKiwi(
-  schemaDeflated: Uint8Array,
-  dataRaw: Uint8Array,
-  version = FIG_KIWI_DEFAULT_VERSION
-): Uint8Array {
-  let dataCompressed: Uint8Array
-  const zstdCompress: ((data: Uint8Array) => Uint8Array) | undefined = (() => {
-    const g = globalThis as { Bun?: { zstdCompressSync?: (data: Uint8Array) => Uint8Array } }
-    return g.Bun?.zstdCompressSync
-  })()
-  if (zstdCompress) {
-    dataCompressed = zstdCompress(dataRaw)
-  } else {
-    dataCompressed = deflateSync(dataRaw)
-  }
-
-  const total = 8 + 4 + 4 + schemaDeflated.length + 4 + dataCompressed.length
-  const out = new Uint8Array(total)
-  const view = new DataView(out.buffer)
-
-  out.set(new TextEncoder().encode('fig-kiwi'), 0)
-  view.setUint32(8, version, true)
-
-  let offset = 12
-  view.setUint32(offset, schemaDeflated.length, true)
-  offset += 4
-  out.set(schemaDeflated, offset)
-  offset += schemaDeflated.length
-
-  view.setUint32(offset, dataCompressed.length, true)
-  offset += 4
-  out.set(dataCompressed, offset)
-
-  return out
-}

packages/kiwi/package.json

@@ -28,6 +28,12 @@
       "import": "./dist/fig/codec.js",
       "default": "./dist/fig/codec.js"
     },
+    "./fig/container": {
+      "types": "./dist/src/fig/container.d.ts",
+      "bun": "./src/fig/container.ts",
+      "import": "./dist/fig/container.js",
+      "default": "./dist/fig/container.js"
+    },
     "./fig/parse": {
       "types": "./dist/src/fig/parse.d.ts",
       "bun": "./src/fig/parse.ts",

packages/kiwi/scripts/smoke-dist.ts

@@ -1,4 +1,5 @@
 import { getSchemaBytes, initCodec, isCodecReady } from '../dist/fig/codec.js'
+import { buildFigKiwi, parseFigKiwiChunks } from '../dist/fig/container.js'
 import { parseFigKiwiContainer } from '../dist/fig/parse.js'
 import { figmaSchema, getKiwiMessageType, parseSchema, validateSchema } from '../dist/index.js'
 
@@ -27,3 +28,8 @@ if (!isCodecReady() || getSchemaBytes().length === 0) {
 if (parseFigKiwiContainer(new TextEncoder().encode('not-fig-kiwi')) !== null) {
   throw new Error('Failed to reject invalid FIG Kiwi container')
 }
+
+const figKiwi = buildFigKiwi(new Uint8Array([1]), new Uint8Array([2]))
+if (parseFigKiwiChunks(figKiwi)?.length !== 2) {
+  throw new Error('Failed to read built FIG Kiwi container chunks')
+}

packages/kiwi/src/fig/container.ts

@@ -0,0 +1,64 @@
+import { deflateSync, inflateSync } from 'fflate'
+
+export const FIG_KIWI_DEFAULT_VERSION = 101
+
+export function parseFigKiwiChunks(binary: Uint8Array): Uint8Array[] | null {
+  const header = new TextDecoder().decode(binary.slice(0, 8))
+  if (header !== 'fig-kiwi') return null
+
+  const view = new DataView(binary.buffer, binary.byteOffset, binary.byteLength)
+  let offset = 12
+
+  const chunks: Uint8Array[] = []
+  while (offset < binary.length) {
+    const chunkLen = view.getUint32(offset, true)
+    offset += 4
+    chunks.push(binary.slice(offset, offset + chunkLen))
+    offset += chunkLen
+  }
+  return chunks.length >= 2 ? chunks : null
+}
+
+export function decompressFigKiwiData(compressed: Uint8Array): Uint8Array {
+  try {
+    return inflateSync(compressed)
+  } catch {
+    throw new Error('Failed to decompress fig-kiwi data')
+  }
+}
+
+export async function decompressFigKiwiDataAsync(compressed: Uint8Array): Promise<Uint8Array> {
+  try {
+    return inflateSync(compressed)
+  } catch {
+    const fzstd = await import('fzstd')
+    return fzstd.decompress(compressed)
+  }
+}
+
+export function buildFigKiwi(
+  schemaDeflated: Uint8Array,
+  dataRaw: Uint8Array,
+  version = FIG_KIWI_DEFAULT_VERSION
+): Uint8Array {
+  const dataDeflated = deflateSync(dataRaw)
+
+  const total = 8 + 4 + 4 + schemaDeflated.length + 4 + dataDeflated.length
+  const out = new Uint8Array(total)
+  const view = new DataView(out.buffer)
+
+  out.set(new TextEncoder().encode('fig-kiwi'), 0)
+  view.setUint32(8, version, true)
+
+  let offset = 12
+  view.setUint32(offset, schemaDeflated.length, true)
+  offset += 4
+  out.set(schemaDeflated, offset)
+  offset += schemaDeflated.length
+
+  view.setUint32(offset, dataDeflated.length, true)
+  offset += 4
+  out.set(dataDeflated, offset)
+
+  return out
+}

packages/kiwi/tests/container.test.ts

@@ -0,0 +1,44 @@
+import { describe, expect, test } from 'bun:test'
+
+import { deflateSync } from 'fflate'
+
+import {
+  buildFigKiwi,
+  decompressFigKiwiData,
+  decompressFigKiwiDataAsync,
+  FIG_KIWI_DEFAULT_VERSION,
+  parseFigKiwiChunks
+} from '../src/fig/container'
+
+describe('Figma FIG Kiwi container helpers', () => {
+  test('builds and parses fig-kiwi chunks', () => {
+    const schemaDeflated = new Uint8Array([1, 2, 3])
+    const dataRaw = new TextEncoder().encode('payload')
+    const binary = buildFigKiwi(schemaDeflated, dataRaw)
+
+    const chunks = parseFigKiwiChunks(binary)
+
+    expect(chunks).not.toBeNull()
+    expect(chunks?.[0]).toEqual(schemaDeflated)
+    expect(chunks?.[1]).toEqual(deflateSync(dataRaw))
+  })
+
+  test('uses the default container version', () => {
+    const binary = buildFigKiwi(new Uint8Array([1]), new Uint8Array([2]))
+    const view = new DataView(binary.buffer, binary.byteOffset, binary.byteLength)
+
+    expect(view.getUint32(8, true)).toBe(FIG_KIWI_DEFAULT_VERSION)
+  })
+
+  test('decompresses deflated data synchronously and asynchronously', async () => {
+    const dataRaw = new TextEncoder().encode('payload')
+    const deflated = deflateSync(dataRaw)
+
+    expect(decompressFigKiwiData(deflated)).toEqual(dataRaw)
+    await expect(decompressFigKiwiDataAsync(deflated)).resolves.toEqual(dataRaw)
+  })
+
+  test('rejects non fig-kiwi data', () => {
+    expect(parseFigKiwiChunks(new TextEncoder().encode('not-fig-kiwi'))).toBeNull()
+  })
+})

packages/kiwi/tsdown.config.ts

@@ -21,6 +21,7 @@ export default defineConfig({
     'schema-runtime': './src/schema-runtime/index.ts',
     fig: './src/fig/index.ts',
     'fig/codec': './src/fig/codec.ts',
+    'fig/container': './src/fig/container.ts',
     'fig/parse': './src/fig/parse.ts'
   },
   plugins: [rawText()],