Export IS_BROWSER from core, replace all raw typeof window checks

- Add IS_BROWSER constant to core/constants.ts, rewrite IS_TAURI to use it
- Replace 9 raw 'typeof window' checks across canvaskit, fig-export,
  figma-api, fig-file, fonts, SafariBanner, use-chat
- Promote no-typeof-window-check lint rule from warn to error
- Extract array mutation helpers (updateArrayItem, removeArrayItem,
  toggleArrayVisibility) into useMultiProps — DRY up FillSection and
  StrokeSection (removes 20+ duplicated for-loops)

lint/plugin.js

@@ -223,7 +223,7 @@ const noTypeofWindowCheck = {
   },
   create(context) {
     const file = context.filename ?? context.getFilename?.()
-    if (file?.endsWith('constants.ts') || file?.endsWith('fonts.ts')) return {}
+    if (file?.endsWith('constants.ts')) return {}
 
     return {
       BinaryExpression(node) {

oxlint.json

@@ -118,7 +118,7 @@
     "open-pencil/no-hand-rolled-color": "error",
     "open-pencil/no-raw-console-format": "off",
     "open-pencil/no-silent-catch": "error",
-    "open-pencil/no-typeof-window-check": "warn"
+    "open-pencil/no-typeof-window-check": "error"
   },
   "overrides": [
     {

packages/core/src/canvaskit.ts

@@ -1,5 +1,7 @@
 import CanvasKitInit, { type CanvasKit } from 'canvaskit-wasm'
 
+import { IS_BROWSER } from './constants'
+
 let instance: CanvasKit | null = null
 
 export type GpuBackend = 'webgl' | 'webgpu'
@@ -16,7 +18,7 @@ export interface CanvasKitOptions {
 }
 
 function detectBackend(): GpuBackend {
-  if (typeof window === 'undefined') return 'webgl'
+  if (!IS_BROWSER) return 'webgl'
   const params = new URLSearchParams(window.location.search)
   if (params.get('gpu') === 'webgpu' && 'gpu' in navigator) return 'webgpu'
   return 'webgl'
@@ -45,7 +47,7 @@ export async function getCanvasKit(options?: CanvasKitOptions): Promise<CanvasKi
   activeBackend = backend
 
   const defaultLocate = (file: string) => {
-    if (typeof window !== 'undefined') return `/${file}`
+    if (IS_BROWSER) return `/${file}`
     return file
   }
 

packages/core/src/constants.ts

@@ -1,6 +1,7 @@
 import type { Color } from './types'
 
-export const IS_TAURI = typeof window !== 'undefined' && '__TAURI_INTERNALS__' in window
+export const IS_BROWSER = typeof window !== 'undefined'
+export const IS_TAURI = IS_BROWSER && '__TAURI_INTERNALS__' in window
 
 export const BLACK: Color = { r: 0, g: 0, b: 0, a: 1 }
 export const TRANSPARENT: Color = { r: 0, g: 0, b: 0, a: 0 }

packages/core/src/fig-export.ts

@@ -1,6 +1,6 @@
 import { zipSync, deflateSync, type Zippable } from 'fflate'
 
-import { CANVAS_BG_COLOR, IS_TAURI } from './constants'
+import { CANVAS_BG_COLOR, IS_BROWSER, IS_TAURI } from './constants'
 import { sceneNodeToKiwi, fractionalPosition, buildFigKiwi, buildFontDigestMap } from './kiwi-serialize'
 import { initCodec, getCompiledSchema, getSchemaBytes } from './kiwi/codec'
 import { stringToGuid } from './kiwi/kiwi-convert'
@@ -271,7 +271,7 @@ export function compressFigDataSync(
 }
 
 function canUseWorker(): boolean {
-  return typeof Worker !== 'undefined' && typeof window !== 'undefined'
+  return typeof Worker !== 'undefined' && IS_BROWSER
 }
 
 function compressViaWorker(

packages/core/src/figma-api.ts

@@ -7,6 +7,7 @@ import type {
   VariableValue
 } from './scene-graph'
 import type { Rect, Vector } from './types'
+import { IS_BROWSER } from './constants'
 import { copyFills, copyStrokes, copyEffects } from './copy'
 
 import {
@@ -337,8 +338,8 @@ export class FigmaAPI implements NodeProxyHost {
         const padding = 80
         const contentW = maxX - minX + padding * 2
         const contentH = maxY - minY + padding * 2
-        const viewW = typeof window !== 'undefined' ? window.innerWidth : 1280
-        const viewH = typeof window !== 'undefined' ? window.innerHeight : 720
+        const viewW = IS_BROWSER ? window.innerWidth : 1280
+        const viewH = IS_BROWSER ? window.innerHeight : 720
         const zoom = Math.min(viewW / contentW, viewH / contentH, 1)
         this._viewport = { x: (minX + maxX) / 2, y: (minY + maxY) / 2, zoom }
       }

packages/core/src/fonts.ts

@@ -2,6 +2,7 @@ import type { CanvasKit, TypefaceFontProvider } from 'canvaskit-wasm'
 
 import {
   DEFAULT_FONT_FAMILY,
+  IS_BROWSER,
   CJK_FALLBACK_FAMILIES_MACOS,
   CJK_FALLBACK_FAMILIES_WINDOWS,
   CJK_FALLBACK_FAMILIES_LINUX,
@@ -17,8 +18,6 @@ export interface FontInfo {
   postscriptName: string
 }
 
-const IS_BROWSER = typeof window !== 'undefined'
-
 const loadedFamilies = new Map<string, ArrayBuffer>()
 let fontProvider: TypefaceFontProvider | null = null
 

packages/core/src/kiwi/fig-file.ts

@@ -1,6 +1,7 @@
 import { unzipSync, inflateSync } from 'fflate'
 import { decompress as zstdDecompress } from 'fzstd'
 
+import { IS_BROWSER } from '../constants'
 import { importNodeChanges } from './fig-import'
 import { decodeBinarySchema, compileSchema, ByteBuffer } from './kiwi-schema'
 import { isZstdCompressed } from './protocol'
@@ -129,7 +130,7 @@ function parseViaWorker(buffer: ArrayBuffer): Promise<SceneGraph> {
 }
 
 export async function parseFigFile(buffer: ArrayBuffer): Promise<SceneGraph> {
-  if (typeof Worker !== 'undefined' && typeof window !== 'undefined') {
+  if (typeof Worker !== 'undefined' && IS_BROWSER) {
     const copy = buffer.slice(0)
     try {
       return await parseViaWorker(buffer)

src/components/SafariBanner.vue

@@ -1,10 +1,10 @@
 <script setup lang="ts">
 import { useLocalStorage } from '@vueuse/core'
 
-import { IS_TAURI } from '@/constants'
+import { IS_BROWSER, IS_TAURI } from '@/constants'
 
 const dismissed = useLocalStorage('safari-banner-dismissed', false)
-const show = !IS_TAURI && typeof window !== 'undefined' && !window.showSaveFilePicker
+const show = !IS_TAURI && IS_BROWSER && !window.showSaveFilePicker
 </script>
 
 <template>

src/components/properties/FillSection.vue

@@ -22,7 +22,7 @@ import { colorToCSS, colorToHexRaw } from '@open-pencil/core'
 import type { Fill, Variable, Color } from '@open-pencil/core'
 
 const { store } = useNodeProps()
-const { nodes, isMulti, active, activeNode, isArrayMixed } = useMultiProps()
+const { nodes, isMulti, active, activeNode, targetNodes, isArrayMixed, updateArrayItem, removeArrayItem, toggleArrayVisibility } = useMultiProps()
 
 const fillsAreMixed = computed(() => isArrayMixed('fills'))
 
@@ -56,50 +56,26 @@ function resolvedSwatchStyle(variable: Variable): string {
 }
 
 function updateFill(index: number, fill: Fill) {
-  for (const n of isMulti.value ? nodes.value : [activeNode.value]) {
-    if (!n) continue
-    const fills = [...n.fills]
-    fills[index] = fill
-    store.updateNodeWithUndo(n.id, { fills }, 'Change fill')
-  }
+  updateArrayItem('fills', index, fill, 'Change fill')
 }
 
 function updateOpacity(index: number, opacity: number) {
-  for (const n of isMulti.value ? nodes.value : [activeNode.value]) {
-    if (!n) continue
-    const fills = [...n.fills]
-    fills[index] = { ...fills[index], opacity: Math.max(0, Math.min(1, opacity / 100)) }
-    store.updateNodeWithUndo(n.id, { fills }, 'Change fill')
-  }
+  updateArrayItem('fills', index, { opacity: Math.max(0, Math.min(1, opacity / 100)) }, 'Change fill')
 }
 
 function toggleVisibility(index: number) {
-  for (const n of isMulti.value ? nodes.value : [activeNode.value]) {
-    if (!n) continue
-    const fills = [...n.fills]
-    fills[index] = { ...fills[index], visible: !fills[index].visible }
-    store.updateNodeWithUndo(n.id, { fills }, 'Change fill')
-  }
+  toggleArrayVisibility('fills', index)
 }
 
 function add() {
-  if (isMulti.value) {
-    for (const n of nodes.value) {
-      store.updateNodeWithUndo(n.id, { fills: [{ ...DEFAULT_SHAPE_FILL }] }, 'Set fill')
-    }
-    store.requestRender()
-  } else {
-    const n = activeNode.value
-    if (!n) return
-    store.updateNodeWithUndo(n.id, { fills: [...n.fills, { ...DEFAULT_SHAPE_FILL }] }, 'Add fill')
+  for (const n of targetNodes()) {
+    const fills = isMulti.value ? [{ ...DEFAULT_SHAPE_FILL }] : [...n.fills, { ...DEFAULT_SHAPE_FILL }]
+    store.updateNodeWithUndo(n.id, { fills }, isMulti.value ? 'Set fill' : 'Add fill')
   }
 }
 
 function remove(index: number) {
-  for (const n of isMulti.value ? nodes.value : [activeNode.value]) {
-    if (!n) continue
-    store.updateNodeWithUndo(n.id, { fills: n.fills.filter((_, i) => i !== index) }, 'Remove fill')
-  }
+  removeArrayItem('fills', index, 'Remove fill')
 }
 
 const searchTerm = ref('')

src/components/properties/StrokeSection.vue

@@ -20,7 +20,7 @@ import type { Color, SceneNode, Stroke } from '@open-pencil/core'
 type StrokeSides = 'ALL' | 'TOP' | 'BOTTOM' | 'LEFT' | 'RIGHT' | 'CUSTOM'
 
 const { store } = useNodeProps()
-const { nodes, isMulti, active, activeNode, isArrayMixed } = useMultiProps()
+const { nodes, isMulti, active, activeNode, targetNodes, isArrayMixed, updateArrayItem, removeArrayItem, toggleArrayVisibility } = useMultiProps()
 
 const strokesAreMixed = computed(() => isArrayMixed('strokes'))
 
@@ -59,47 +59,26 @@ const hasStrokes = computed(
 const sideMenuOpen = ref(false)
 
 function updateColor(index: number, color: Color) {
-  for (const n of isMulti.value ? nodes.value : [activeNode.value]) {
-    if (!n) continue
-    const strokes = [...n.strokes]
-    strokes[index] = { ...strokes[index], color }
-    store.updateNodeWithUndo(n.id, { strokes }, 'Change stroke')
-  }
+  updateArrayItem('strokes', index, { color }, 'Change stroke')
 }
 
 function updateWeight(index: number, weight: number) {
-  for (const n of isMulti.value ? nodes.value : [activeNode.value]) {
-    if (!n) continue
-    const strokes = [...n.strokes]
-    strokes[index] = { ...strokes[index], weight }
-    store.updateNodeWithUndo(n.id, { strokes }, 'Change stroke')
-  }
+  updateArrayItem('strokes', index, { weight }, 'Change stroke')
 }
 
 function updateOpacity(index: number, opacity: number) {
-  for (const n of isMulti.value ? nodes.value : [activeNode.value]) {
-    if (!n) continue
-    const strokes = [...n.strokes]
-    strokes[index] = { ...strokes[index], opacity: Math.max(0, Math.min(1, opacity / 100)) }
-    store.updateNodeWithUndo(n.id, { strokes }, 'Change stroke')
-  }
+  updateArrayItem('strokes', index, { opacity: Math.max(0, Math.min(1, opacity / 100)) }, 'Change stroke')
 }
 
 function updateAlign(align: Stroke['align']) {
-  for (const n of isMulti.value ? nodes.value : [activeNode.value]) {
-    if (!n) continue
+  for (const n of targetNodes()) {
     const strokes = n.strokes.map((s) => ({ ...s, align }))
     store.updateNodeWithUndo(n.id, { strokes }, 'Change stroke align')
   }
 }
 
 function toggleVisibility(index: number) {
-  for (const n of isMulti.value ? nodes.value : [activeNode.value]) {
-    if (!n) continue
-    const strokes = [...n.strokes]
-    strokes[index] = { ...strokes[index], visible: !strokes[index].visible }
-    store.updateNodeWithUndo(n.id, { strokes }, 'Change stroke')
-  }
+  toggleArrayVisibility('strokes', index)
 }
 
 function add() {
@@ -110,32 +89,18 @@ function add() {
     visible: true,
     align: 'CENTER'
   }
-  if (isMulti.value) {
-    for (const n of nodes.value) {
-      store.updateNodeWithUndo(n.id, { strokes: [stroke] }, 'Set stroke')
-    }
-    store.requestRender()
-  } else {
-    const n = activeNode.value
-    if (!n) return
-    store.updateNodeWithUndo(n.id, { strokes: [...n.strokes, stroke] }, 'Add stroke')
+  for (const n of targetNodes()) {
+    const strokes = isMulti.value ? [stroke] : [...n.strokes, stroke]
+    store.updateNodeWithUndo(n.id, { strokes }, isMulti.value ? 'Set stroke' : 'Add stroke')
   }
 }
 
 function remove(index: number) {
-  for (const n of isMulti.value ? nodes.value : [activeNode.value]) {
-    if (!n) continue
-    store.updateNodeWithUndo(
-      n.id,
-      { strokes: n.strokes.filter((_, i) => i !== index) },
-      'Remove stroke'
-    )
-  }
+  removeArrayItem('strokes', index, 'Remove stroke')
 }
 
 function selectSide(side: StrokeSides) {
-  for (const n of isMulti.value ? nodes.value : [activeNode.value]) {
-    if (!n) continue
+  for (const n of targetNodes()) {
     const weight = n.strokes.length > 0 ? n.strokes[0].weight : 1
     if (side === 'ALL') {
       store.updateNodeWithUndo(
@@ -193,8 +158,7 @@ function updateBorderWeight(side: 'top' | 'right' | 'bottom' | 'left', value: nu
     bottom: 'borderBottomWeight',
     left: 'borderLeftWeight'
   } as const
-  for (const n of isMulti.value ? nodes.value : [activeNode.value]) {
-    if (!n) continue
+  for (const n of targetNodes()) {
     store.updateNodeWithUndo(
       n.id,
       { [fieldMap[side]]: value } as Partial<SceneNode>,

src/composables/use-chat.ts

@@ -15,6 +15,7 @@ import {
   AI_PROVIDERS,
   DEFAULT_AI_MODEL,
   DEFAULT_AI_PROVIDER,
+  IS_BROWSER,
   IS_TAURI,
   setPexelsApiKey,
   setUnsplashAccessKey
@@ -41,7 +42,7 @@ function migrateLegacyStorage() {
   }
 }
 
-if (typeof window !== 'undefined') migrateLegacyStorage()
+if (IS_BROWSER) migrateLegacyStorage()
 
 const providerID = useLocalStorage<AIProviderID>(
   `${STORAGE_PREFIX}ai-provider`,
@@ -270,7 +271,7 @@ function resetChat() {
   transportDirty = false
 }
 
-if (typeof window !== 'undefined') {
+if (IS_BROWSER) {
   window.__OPEN_PENCIL_SET_TRANSPORT__ = (factory) => {
     overrideTransport = factory
   }

src/composables/use-multi-props.ts

@@ -43,6 +43,46 @@ export function useMultiProps() {
     return all.some((n) => JSON.stringify(n[key]) !== first)
   }
 
+  type ArrayPropKey = 'fills' | 'strokes' | 'effects'
+
+  function targetNodes(): SceneNode[] {
+    if (isMulti.value) return nodes.value
+    return activeNode.value ? [activeNode.value] : []
+  }
+
+  function updateArrayItem(
+    key: ArrayPropKey,
+    index: number,
+    patch: Record<string, unknown>,
+    label: string
+  ) {
+    for (const n of targetNodes()) {
+      const arr = [...n[key]]
+      arr[index] = { ...arr[index], ...patch } as (typeof arr)[number]
+      store.updateNodeWithUndo(n.id, { [key]: arr } as Partial<SceneNode>, label)
+    }
+  }
+
+  function removeArrayItem(key: ArrayPropKey, index: number, label: string) {
+    for (const n of targetNodes()) {
+      store.updateNodeWithUndo(
+        n.id,
+        { [key]: (n[key] as unknown[]).filter((_, i) => i !== index) } as Partial<SceneNode>,
+        label
+      )
+    }
+  }
+
+  function toggleArrayVisibility(key: ArrayPropKey, index: number) {
+    for (const n of targetNodes()) {
+      const items = n[key] as Array<{ visible: boolean }>
+      if (!items[index]) continue
+      const arr = [...n[key]]
+      arr[index] = { ...arr[index], visible: !items[index].visible }
+      store.updateNodeWithUndo(n.id, { [key]: arr } as Partial<SceneNode>, `Toggle ${key} visibility`)
+    }
+  }
+
   return {
     store,
     node,
@@ -50,9 +90,13 @@ export function useMultiProps() {
     isMulti,
     active,
     activeNode,
+    targetNodes,
     prop,
     merged,
     updateAllWithUndo,
+    updateArrayItem,
+    removeArrayItem,
+    toggleArrayVisibility,
     isArrayMixed
   }
 }

src/constants.ts

@@ -1,4 +1,5 @@
 export {
+  IS_BROWSER,
   IS_TAURI,
   SELECTION_COLOR,
   COMPONENT_COLOR,