feat(v-on): cache handlers

packages/compiler-core/src/utils.ts

@@ -21,13 +21,14 @@ import {
   ElementCodegenNode,
   SlotOutletCodegenNode,
   ComponentCodegenNode,
-  ExpressionNode
+  ExpressionNode,
+  IfBranchNode
 } from './ast'
 import { parse } from 'acorn'
 import { walk } from 'estree-walker'
 import { TransformContext } from './transform'
 import { OPEN_BLOCK, MERGE_PROPS, RENDER_SLOT } from './runtimeHelpers'
-import { isString, isFunction } from '@vue/shared'
+import { isString, isFunction, isObject } from '@vue/shared'
 
 // cache node requires
 // lazy require dependencies so that they don't end up in rollup's dep graph
@@ -250,3 +251,51 @@ export function toValidAssetId(
 export function isEmptyExpression(node: ExpressionNode) {
   return node.type === NodeTypes.SIMPLE_EXPRESSION && !node.content.trim()
 }
+
+// Check if a node contains expressions that reference current context scope ids
+export function hasScopeRef(
+  node: TemplateChildNode | IfBranchNode | ExpressionNode | undefined,
+  ids: TransformContext['identifiers']
+): boolean {
+  if (!node || Object.keys(ids).length === 0) {
+    return false
+  }
+  switch (node.type) {
+    case NodeTypes.ELEMENT:
+      for (let i = 0; i < node.props.length; i++) {
+        const p = node.props[i]
+        if (
+          p.type === NodeTypes.DIRECTIVE &&
+          (hasScopeRef(p.arg, ids) || hasScopeRef(p.exp, ids))
+        ) {
+          return true
+        }
+      }
+      return node.children.some(c => hasScopeRef(c, ids))
+    case NodeTypes.FOR:
+      if (hasScopeRef(node.source, ids)) {
+        return true
+      }
+      return node.children.some(c => hasScopeRef(c, ids))
+    case NodeTypes.IF:
+      return node.branches.some(b => hasScopeRef(b, ids))
+    case NodeTypes.IF_BRANCH:
+      if (hasScopeRef(node.condition, ids)) {
+        return true
+      }
+      return node.children.some(c => hasScopeRef(c, ids))
+    case NodeTypes.SIMPLE_EXPRESSION:
+      return (
+        !node.isStatic &&
+        isSimpleIdentifier(node.content) &&
+        !!ids[node.content]
+      )
+    case NodeTypes.COMPOUND_EXPRESSION:
+      return node.children.some(c => isObject(c) && hasScopeRef(c, ids))
+    case NodeTypes.INTERPOLATION:
+      return hasScopeRef(node.content, ids)
+    default:
+      // TextNode or CommentNode
+      return false
+  }
+}