refactor: id rewrite of vapor v-for

Author: sxzz

packages/compiler-vapor/__tests__/transforms/__snapshots__/vFor.spec.ts.snap

@@ -1,29 +1,31 @@
 // Vitest Snapshot v1, https://vitest.dev/guide/snapshot.html
 
 exports[`compiler: v-for > basic v-for 1`] = `
-"import { template as _template, fragment as _fragment, children as _children, on as _on, setText as _setText, renderEffect as _renderEffect, createFor as _createFor, append as _append } from 'vue/vapor';
+"import { template as _template, fragment as _fragment, renderEffect as _renderEffect, children as _children, on as _on, setText as _setText, createFor as _createFor, append as _append } from 'vue/vapor';
 
 export function render(_ctx) {
   const t0 = _template("<div></div>")
   const t1 = _fragment()
   const n0 = t1()
   const n1 = _createFor(() => (_ctx.items), (_block) => {
+    let item
+    _renderEffect(() => {
+      ([item] = _block.s);
+    })
     const n2 = t0()
     const { 0: [n3],} = _children(n2)
-    _on(n3, "click", $event => (_ctx.remove(_block.s[0])))
-    const _updateEffect = () => {
-      const [item] = _block.s
+    _on(n3, "click", $event => (_ctx.remove(item)))
+    _renderEffect(() => {
       _setText(n3, item)
-    }
-    _renderEffect(_updateEffect)
-    return [n2, _updateEffect]
+    })
+    return n2
   })
   _append(n0, n1)
   return n0
 }"
 `;
 
-exports[`compiler: v-for > basic v-for 2`] = `
+exports[`compiler: v-for > no value 1`] = `
 "import { template as _template, fragment as _fragment, createFor as _createFor, append as _append } from 'vue/vapor';
 
 export function render(_ctx) {
@@ -32,7 +34,37 @@ export function render(_ctx) {
   const n0 = t1()
   const n1 = _createFor(() => (_ctx.items), (_block) => {
     const n2 = t0()
-    return [n2, () => {}]
+    return n2
+  })
+  _append(n0, n1)
+  return n0
+}"
+`;
+
+exports[`compiler: v-for > object de-structured value 1`] = `
+"import { template as _template, fragment as _fragment, renderEffect as _renderEffect, children as _children, createTextNode as _createTextNode, append as _append, setText as _setText, createFor as _createFor } from 'vue/vapor';
+
+export function render(_ctx) {
+  const t0 = _template("<span></span>")
+  const t1 = _fragment()
+  const n0 = t1()
+  const n1 = _createFor(() => (_ctx.items), (_block) => {
+    let id, value
+    _renderEffect(() => {
+      ([{ id, value }] = _block.s);
+    })
+    const n2 = t0()
+    const { 0: [n5],} = _children(n2)
+    const n3 = _createTextNode()
+    const n4 = _createTextNode()
+    _append(n5, n3, n4)
+    _renderEffect(() => {
+      _setText(n3, id)
+    })
+    _renderEffect(() => {
+      _setText(n4, value)
+    })
+    return n2
   })
   _append(n0, n1)
   return n0

packages/compiler-vapor/__tests__/transforms/vFor.spec.ts

@@ -66,8 +66,15 @@ describe('compiler: v-for', () => {
     expect((ir.operation[0] as ForIRNode).render.effect).lengthOf(1)
   })
 
-  test('basic v-for', () => {
+  test('no value', () => {
     const { code } = compileWithVFor(`<div v-for=" of items">item</div>`)
     expect(code).matchSnapshot()
   })
+
+  test('object de-structured value', () => {
+    const { code } = compileWithVFor(
+      '<span v-for="({ id, value }) in items">{{ id }}{{ value }}</span>',
+    )
+    expect(code).matchSnapshot()
+  })
 })

packages/compiler-vapor/src/generate.ts

@@ -7,9 +7,9 @@ import {
   advancePositionWithMutation,
   locStub,
 } from '@vue/compiler-dom'
-import type { IREffect, RootIRNode, VaporHelper } from './ir'
+import type { RootIRNode, VaporHelper } from './ir'
 import { SourceMapGenerator } from 'source-map-js'
-import { extend, isString, remove } from '@vue/shared'
+import { extend, isString } from '@vue/shared'
 import type { ParserPlugin } from '@babel/parser'
 import { genTemplate } from './generators/template'
 import { genBlockFunctionContent } from './generators/block'
@@ -69,22 +69,19 @@ export class CodegenContext {
     return `_${name}`
   }
 
-  identifiers: Record<string, string[]> = Object.create(null)
-  withId = <T>(fn: () => T, map: Record<string, string | null>): T => {
+  identifiers: Record<string, number> = Object.create(null)
+  withId = <T>(fn: () => T, ids: string[]): T => {
     const { identifiers } = this
-    const ids = Object.keys(map)
-
     for (const id of ids) {
-      identifiers[id] ||= []
-      identifiers[id].unshift(map[id] || id)
+      if (identifiers[id] === undefined) identifiers[id] = 0
+      identifiers[id]!++
     }
 
     const ret = fn()
-    ids.forEach(id => remove(identifiers[id], map[id] || id))
+    ids.forEach(id => identifiers[id]!--)
 
     return ret
   }
-  genEffect?: (effects: IREffect[]) => CodeFragment[]
 
   constructor(
     public ir: RootIRNode,

packages/compiler-vapor/src/generators/block.ts

@@ -21,13 +21,15 @@ export function genBlockFunction(
   oper: BlockFunctionIRNode,
   context: CodegenContext,
   args: CodeFragment[] = [],
-  returnValue?: () => CodeFragment[],
+  preamble: CodeFragment[] = [],
+  returnValue?: CodeFragment[],
 ): CodeFragment[] {
   return [
     '(',
     ...args,
     ') => {',
     INDENT_START,
+    ...preamble,
     ...genBlockFunctionContent(oper, context, returnValue),
     INDENT_END,
     NEWLINE,
@@ -38,7 +40,7 @@ export function genBlockFunction(
 export function genBlockFunctionContent(
   ir: BlockFunctionIRNode | RootIRNode,
   context: CodegenContext,
-  returnValue?: () => CodeFragment[],
+  returnValue?: CodeFragment[],
 ): CodeFragment[] {
   const { vaporHelper } = context
   const [frag, push] = buildCodeFragment(
@@ -65,11 +67,7 @@ export function genBlockFunctionContent(
   push(...genOperations(ir.operation, context))
   push(...genEffects(ir.effect, context))
 
-  push(
-    NEWLINE,
-    'return ',
-    ...(returnValue ? returnValue() : [`n${ir.dynamic.id}`]),
-  )
+  push(NEWLINE, 'return ', ...(returnValue || [`n${ir.dynamic.id}`]))
 
   return frag
 }

packages/compiler-vapor/src/generators/event.ts

@@ -45,9 +45,10 @@ export function genSetEvent(
       const hasMultipleStatements = exp.content.includes(`;`)
 
       if (isInlineStatement) {
-        const expr = context.withId(() => genExpression(exp, context), {
-          $event: null,
-        })
+        const expr = context.withId(
+          () => genExpression(exp, context),
+          ['$event'],
+        )
         return [
           '$event => ',
           hasMultipleStatements ? '{' : '(',

packages/compiler-vapor/src/generators/expression.ts

@@ -88,9 +88,8 @@ function genIdentifier(
   const { inline, bindingMetadata } = options
   let name: string | undefined = id
 
-  const idMap = identifiers[id]
-  if (idMap && idMap.length) {
-    return [idMap[0], NewlineType.None, loc]
+  if (identifiers[id]) {
+    return [id, NewlineType.None, loc]
   }
 
   if (inline) {

packages/compiler-vapor/src/generators/for.ts

@@ -6,11 +6,14 @@ import {
   INDENT_END,
   INDENT_START,
   NEWLINE,
-  buildCodeFragment,
 } from '../generate'
-import type { ForIRNode, IREffect } from '../ir'
-import { genOperations } from './operation'
-import { NewlineType } from '@vue/compiler-dom'
+import type { ForIRNode } from '../ir'
+import {
+  NewlineType,
+  type SimpleExpressionNode,
+  walkIdentifiers,
+} from '@vue/compiler-dom'
+import type { ArrowFunctionExpression } from '@babel/types'
 
 export function genFor(
   oper: ForIRNode,
@@ -19,73 +22,63 @@ export function genFor(
   const { call, vaporHelper } = context
   const { source, value, key, render } = oper
 
-  const rawValue = value && value.content
   const rawKey = key && key.content
-
   const sourceExpr = ['() => (', ...genExpression(source, context), ')']
-  let updateFn = '_updateEffect'
-  context.genEffect = genEffectInFor
+  const valueIds = value ? extractParams(value) : new Set<string>()
+  const keyIds = key ? extractParams(key) : new Set<string>()
+  const ids = [...valueIds, ...keyIds]
 
-  const idMap: Record<string, string> = {}
-  if (rawValue) idMap[rawValue] = `_block.s[0]`
-  if (rawKey) idMap[rawKey] = `_block.s[1]`
+  let preamble: CodeFragment[] = []
+  if (value || rawKey) {
+    const assignment: CodeFragment[] = ['let ', ids.join(', ')]
 
-  const blockRet = (): CodeFragment[] => [
-    `[n${render.dynamic.id!}, ${updateFn}]`,
-  ]
+    preamble = [
+      NEWLINE,
+      ...assignment,
+      NEWLINE,
+      ...call(vaporHelper('renderEffect'), [
+        '() => {',
+        INDENT_START,
+        NEWLINE,
+        '(',
+        '[',
+        value && [value.content, NewlineType.None, value.loc],
+        rawKey && ', ',
+        rawKey && [rawKey, NewlineType.None, key.loc],
+        '] = _block.s',
+        ');',
+        INDENT_END,
+        NEWLINE,
+        '}',
+      ]),
+    ]
+  }
 
+  const blockRet: CodeFragment[] = [`n${render.dynamic.id!}`]
   const blockFn = context.withId(
-    () => genBlockFunction(render, context, ['_block'], blockRet),
-    idMap,
+    () => genBlockFunction(render, context, ['_block'], preamble, blockRet),
+    ids,
   )
 
-  context.genEffect = undefined
-
   return [
     NEWLINE,
     `const n${oper.id} = `,
     ...call(vaporHelper('createFor'), sourceExpr, blockFn),
   ]
+}
 
-  function genEffectInFor(effects: IREffect[]): CodeFragment[] {
-    if (!effects.length) {
-      updateFn = '() => {}'
-      return []
-    }
-
-    const [frag, push] = buildCodeFragment(INDENT_START)
-    // const [value, key] = _block.s
-    if (rawValue || rawKey) {
-      push(
-        NEWLINE,
-        'const ',
-        '[',
-        rawValue && [rawValue, NewlineType.None, value.loc],
-        rawKey && ', ',
-        rawKey && [rawKey, NewlineType.None, key.loc],
-        '] = _block.s',
-      )
-    }
-
-    const idMap: Record<string, string | null> = {}
-    if (value) idMap[value.content] = null
-    if (key) idMap[key.content] = null
-    context.withId(() => {
-      effects.forEach(effect =>
-        push(...genOperations(effect.operations, context)),
-      )
-    }, idMap)
-
-    push(INDENT_END)
-
-    return [
-      NEWLINE,
-      `const ${updateFn} = () => {`,
-      ...frag,
-      NEWLINE,
-      '}',
-      NEWLINE,
-      `${vaporHelper('renderEffect')}(${updateFn})`,
-    ]
+function extractParams(node: SimpleExpressionNode) {
+  const ids = new Set<string>()
+  if (node.ast === null || node.ast === false) {
+    ids.add(node.content)
+  } else {
+    walkIdentifiers(
+      node.ast as ArrowFunctionExpression,
+      (id, parent, parentStack, isReference, isLocal) => {
+        if (isLocal) ids.add(id.name)
+      },
+      true,
+    )
   }
+  return ids
 }

packages/compiler-vapor/src/generators/operation.ts

@@ -25,7 +25,7 @@ export function genOperations(opers: OperationNode[], context: CodegenContext) {
   return frag
 }
 
-function genOperation(
+export function genOperation(
   oper: OperationNode,
   context: CodegenContext,
 ): CodeFragment[] {
@@ -60,17 +60,14 @@ function genOperation(
 }
 
 export function genEffects(effects: IREffect[], context: CodegenContext) {
-  if (context.genEffect) {
-    return context.genEffect(effects)
-  }
   const [frag, push] = buildCodeFragment()
   for (const effect of effects) {
     push(...genEffect(effect, context))
   }
   return frag
 }
 
-function genEffect({ operations }: IREffect, context: CodegenContext) {
+export function genEffect({ operations }: IREffect, context: CodegenContext) {
   const { vaporHelper } = context
   const [frag, push] = buildCodeFragment(
     NEWLINE,

packages/runtime-vapor/src/for.ts

@@ -15,7 +15,7 @@ interface ForBlock extends Fragment {
 
 export const createFor = (
   src: () => any[] | Record<string, string> | Set<any> | Map<any, any>,
-  renderItem: (block: ForBlock) => [Block, () => void],
+  renderItem: (block: ForBlock) => Block,
   getKey: ((item: any, index: number) => any) | null,
   getMemo?: (item: any) => any[],
   hydrationNode?: Node,
@@ -47,9 +47,8 @@ export const createFor = (
       memo: getMemo && getMemo(item),
       [fragmentKey]: true,
     })
-    const res = scope.run(() => renderItem(block))!
-    block.nodes = res[0]
-    block.update = res[1]
+    block.nodes = scope.run(() => renderItem(block))!
+    block.update = () => scope.effects.forEach(effect => effect.run())
     if (getMemo) block.update()
     if (parent) insert(block.nodes, parent, anchor)
     return block