fix(v-once): fix v-once usage with v-if and v-for

fix #2035

packages/compiler-core/__tests__/transforms/vOnce.spec.ts

@@ -3,21 +3,17 @@ import {
   transform,
   NodeTypes,
   generate,
-  CompilerOptions
+  CompilerOptions,
+  getBaseTransformPreset
 } from '../../src'
-import { transformOnce } from '../../src/transforms/vOnce'
-import { transformElement } from '../../src/transforms/transformElement'
 import { RENDER_SLOT, SET_BLOCK_TRACKING } from '../../src/runtimeHelpers'
-import { transformBind } from '../../src/transforms/vBind'
-import { transformSlotOutlet } from '../../src/transforms/transformSlotOutlet'
 
 function transformWithOnce(template: string, options: CompilerOptions = {}) {
   const ast = parse(template)
+  const [nodeTransforms, directiveTransforms] = getBaseTransformPreset()
   transform(ast, {
-    nodeTransforms: [transformOnce, transformElement, transformSlotOutlet],
-    directiveTransforms: {
-      bind: transformBind
-    },
+    nodeTransforms,
+    directiveTransforms,
     ...options
   })
   return ast
@@ -102,4 +98,30 @@ describe('compiler: v-once transform', () => {
     })
     expect(generate(root).code).toMatchSnapshot()
   })
+
+  test('with v-if', () => {
+    const root = transformWithOnce(`<div v-if="true" v-once />`)
+    expect(root.cached).toBe(1)
+    expect(root.helpers).toContain(SET_BLOCK_TRACKING)
+    expect(root.children[0]).toMatchObject({
+      type: NodeTypes.IF,
+      // should cache the entire v-if expression, not just a single branch
+      codegenNode: {
+        type: NodeTypes.JS_CACHE_EXPRESSION
+      }
+    })
+  })
+
+  test('with v-for', () => {
+    const root = transformWithOnce(`<div v-for="i in list" v-once />`)
+    expect(root.cached).toBe(1)
+    expect(root.helpers).toContain(SET_BLOCK_TRACKING)
+    expect(root.children[0]).toMatchObject({
+      type: NodeTypes.FOR,
+      // should cache the entire v-for expression, not just a single branch
+      codegenNode: {
+        type: NodeTypes.JS_CACHE_EXPRESSION
+      }
+    })
+  })
 })