refactor(compiler-sfc): improve script setup import expose heuristics

packages/compiler-sfc/__tests__/__snapshots__/compileScript.spec.ts.snap

@@ -206,7 +206,7 @@ return { x }
 
 exports[`SFC compile <script setup> imports imports not used in <template> should not be exposed 1`] = `
 "import { defineComponent as _defineComponent } from 'vue'
-import { FooBar, FooBaz, FooQux, vMyDir, x, y } from './x'
+import { FooBar, FooBaz, FooQux, vMyDir, x, y, z } from './x'
         
 export default _defineComponent({
   setup(__props, { expose }) {
@@ -214,7 +214,7 @@ export default _defineComponent({
 
         const fooBar: FooBar = 1
         
-return { fooBar, FooBaz, FooQux, vMyDir, x }
+return { fooBar, FooBaz, FooQux, vMyDir, x, z }
 }
 
 })"

packages/compiler-sfc/__tests__/compileScript.spec.ts

@@ -213,20 +213,23 @@ defineExpose({ foo: 123 })
     test('imports not used in <template> should not be exposed', () => {
       const { content } = compile(`
         <script setup lang="ts">
-        import { FooBar, FooBaz, FooQux, vMyDir, x, y } from './x'
+        import { FooBar, FooBaz, FooQux, vMyDir, x, y, z } from './x'
         const fooBar: FooBar = 1
         </script>
         <template>
           <FooBaz v-my-dir>{{ x }} {{ yy }}</FooBaz>
           <foo-qux/>
+          <div :id="z + 'y'">FooBar</div>
         </template>
         `)
       assertCode(content)
+      // FooBar: should not be matched by plain text
       // FooBaz: used as PascalCase component
       // FooQux: used as kebab-case component
       // vMyDir: used as directive v-my-dir
       // x: used in interpolation
-      expect(content).toMatch(`return { fooBar, FooBaz, FooQux, vMyDir, x }`)
+      // y: should not be matched by {{ yy }} or 'y' in binding exps
+      expect(content).toMatch(`return { fooBar, FooBaz, FooQux, vMyDir, x, z }`)
     })
   })
 

packages/compiler-sfc/src/cache.ts

@@ -0,0 +1,5 @@
+export function createCache<T>(size = 500) {
+  return __GLOBAL__ || __ESM_BROWSER__
+    ? new Map<string, T>()
+    : (new (require('lru-cache'))(size) as Map<string, T>)
+}

packages/compiler-sfc/src/compileScript.ts

@@ -2,9 +2,14 @@ import MagicString from 'magic-string'
 import {
   BindingMetadata,
   BindingTypes,
+  createRoot,
   locStub,
-  UNREF
+  NodeTypes,
-} from '@vue/compiler-core'
+  transform,
+  parserOptions,
+  UNREF,
+  SimpleExpressionNode
+} from '@vue/compiler-dom'
 import {
   ScriptSetupTextRanges,
   SFCDescriptor,
@@ -14,8 +19,10 @@ import {
 import { parse as _parse, ParserOptions, ParserPlugin } from '@babel/parser'
 import {
   babelParserDefaultPlugins,
+  camelize,
+  capitalize,
   generateCodeFrame,
-  hyphenate
+  makeMap
 } from '@vue/shared'
 import {
   Node,
@@ -49,6 +56,7 @@ import {
 import { compileTemplate, SFCTemplateCompileOptions } from './compileTemplate'
 import { warnExperimental, warnOnce } from './warn'
 import { rewriteDefault } from './rewriteDefault'
+import { createCache } from './cache'
 
 // Special compiler macros
 const DEFINE_PROPS = 'defineProps'
@@ -61,6 +69,10 @@ const $COMPUTED = `$computed`
 const $FROM_REFS = `$fromRefs`
 const $RAW = `$raw`
 
+const isBuiltInDir = makeMap(
+  `once,memo,if,else,else-if,slot,text,html,on,bind,model,show,cloak,is`
+)
+
 export interface SFCScriptCompileOptions {
   /**
    * Scope ID for prefixing injected CSS varialbes.
@@ -319,10 +331,10 @@ export function compileScript(
     }
 
     let isUsedInTemplate = true
-    if (sfc.template && !sfc.template.src) {
+    if (isTS && sfc.template && !sfc.template.src) {
-      isUsedInTemplate = new RegExp(
+      isUsedInTemplate = new RegExp(`\\b${local}\\b`).test(
-        `\\b(?:${local}|${hyphenate(local)})\\b`
+        resolveTemplateUsageCheckString(sfc)
-      ).test(sfc.template.content)
+      )
     }
 
     userImports[local] = {
@@ -2154,3 +2166,53 @@ function toTextRange(node: Node): TextRange {
     end: node.end!
   }
 }
+
+const templateUsageCheckCache = createCache<string>()
+
+function resolveTemplateUsageCheckString(sfc: SFCDescriptor) {
+  const { content, ast } = sfc.template!
+  const cached = templateUsageCheckCache.get(content)
+  if (cached) {
+    return cached
+  }
+
+  let code = ''
+  transform(createRoot([ast]), {
+    nodeTransforms: [
+      node => {
+        if (node.type === NodeTypes.ELEMENT) {
+          if (
+            !parserOptions.isNativeTag!(node.tag) &&
+            !parserOptions.isBuiltInComponent!(node.tag)
+          ) {
+            code += `,${capitalize(camelize(node.tag))}`
+          }
+          for (let i = 0; i < node.props.length; i++) {
+            const prop = node.props[i]
+            if (prop.type === NodeTypes.DIRECTIVE) {
+              if (!isBuiltInDir(prop.name)) {
+                code += `,v${capitalize(camelize(prop.name))}`
+              }
+              if (prop.exp) {
+                code += `,${stripStrings(
+                  (prop.exp as SimpleExpressionNode).content
+                )}`
+              }
+            }
+          }
+        } else if (node.type === NodeTypes.INTERPOLATION) {
+          code += `,${stripStrings(
+            (node.content as SimpleExpressionNode).content
+          )}`
+        }
+      }
+    ]
+  })
+
+  templateUsageCheckCache.set(content, code)
+  return code
+}
+
+function stripStrings(exp: string) {
+  return exp.replace(/'[^']+'|"[^"]+"|`[^`]+`/g, '')
+}

packages/compiler-sfc/src/parse.ts

@@ -12,6 +12,7 @@ import { TemplateCompiler } from './compileTemplate'
 import { Statement } from '@babel/types'
 import { parseCssVars } from './cssVars'
 import { warnExperimental } from './warn'
+import { createCache } from './cache'
 
 export interface SFCParseOptions {
   filename?: string
@@ -89,14 +90,7 @@ export interface SFCParseResult {
   errors: (CompilerError | SyntaxError)[]
 }
 
-const SFC_CACHE_MAX_SIZE = 500
+const sourceToSFC = createCache<SFCParseResult>()
-const sourceToSFC =
-  __GLOBAL__ || __ESM_BROWSER__
-    ? new Map<string, SFCParseResult>()
-    : (new (require('lru-cache'))(SFC_CACHE_MAX_SIZE) as Map<
-        string,
-        SFCParseResult
-      >)
 
 export function parse(
   source: string,