refactor(compiler): further extract babel ast utilities

Author: yyx990803

packages/compiler-core/src/babelUtils.ts

@@ -0,0 +1,231 @@
+import {
+  Identifier,
+  Node,
+  isReferenced,
+  Function,
+  ObjectProperty
+} from '@babel/types'
+import { walk } from 'estree-walker'
+
+export function walkIdentifiers(
+  root: Node,
+  onIdentifier: (
+    node: Identifier,
+    parent: Node,
+    parentStack: Node[],
+    isReference: boolean,
+    isLocal: boolean
+  ) => void,
+  onNode?: (node: Node, parent: Node, parentStack: Node[]) => void | boolean,
+  parentStack: Node[] = [],
+  knownIds: Record<string, number> = Object.create(null),
+  includeAll = false
+) {
+  const rootExp =
+    root.type === 'Program' &&
+    root.body[0].type === 'ExpressionStatement' &&
+    root.body[0].expression
+
+  ;(walk as any)(root, {
+    enter(node: Node & { scopeIds?: Set<string> }, parent: Node | undefined) {
+      parent && parentStack.push(parent)
+      if (
+        parent &&
+        parent.type.startsWith('TS') &&
+        parent.type !== 'TSAsExpression' &&
+        parent.type !== 'TSNonNullExpression' &&
+        parent.type !== 'TSTypeAssertion'
+      ) {
+        return this.skip()
+      }
+      if (onNode && onNode(node, parent!, parentStack) === false) {
+        return this.skip()
+      }
+      if (node.type === 'Identifier') {
+        const isLocal = !!knownIds[node.name]
+        const isRefed = isReferencedIdentifier(node, parent!, parentStack)
+        if (includeAll || (isRefed && !isLocal)) {
+          onIdentifier(node, parent!, parentStack, isRefed, isLocal)
+        }
+      } else if (isFunctionType(node)) {
+        // walk function expressions and add its arguments to known identifiers
+        // so that we don't prefix them
+        for (const p of node.params) {
+          ;(walk as any)(p, {
+            enter(child: Node, parent: Node) {
+              if (
+                child.type === 'Identifier' &&
+                // do not record as scope variable if is a destructured key
+                !isStaticPropertyKey(child, parent) &&
+                // do not record if this is a default value
+                // assignment of a destructured variable
+                !(
+                  parent &&
+                  parent.type === 'AssignmentPattern' &&
+                  parent.right === child
+                )
+              ) {
+                markScopeIdentifier(node, child, knownIds)
+              }
+            }
+          })
+        }
+      } else if (node.type === 'BlockStatement') {
+        // #3445 record block-level local variables
+        for (const stmt of node.body) {
+          if (stmt.type === 'VariableDeclaration') {
+            for (const decl of stmt.declarations) {
+              for (const id of extractIdentifiers(decl.id)) {
+                markScopeIdentifier(node, id, knownIds)
+              }
+            }
+          }
+        }
+      } else if (
+        node.type === 'ObjectProperty' &&
+        parent!.type === 'ObjectPattern'
+      ) {
+        // mark property in destructure pattern
+        ;(node as any).inPattern = true
+      }
+    },
+    leave(node: Node & { scopeIds?: Set<string> }, parent: Node | undefined) {
+      parent && parentStack.pop()
+      if (node !== rootExp && node.scopeIds) {
+        node.scopeIds.forEach((id: string) => {
+          knownIds[id]--
+          if (knownIds[id] === 0) {
+            delete knownIds[id]
+          }
+        })
+      }
+    }
+  })
+}
+
+export function isReferencedIdentifier(
+  id: Identifier,
+  parent: Node | null,
+  parentStack: Node[]
+) {
+  if (!parent) {
+    return true
+  }
+
+  // is a special keyword but parsed as identifier
+  if (id.name === 'arguments') {
+    return false
+  }
+
+  if (isReferenced(id, parent)) {
+    return true
+  }
+
+  // babel's isReferenced check returns false for ids being assigned to, so we
+  // need to cover those cases here
+  switch (parent.type) {
+    case 'AssignmentExpression':
+    case 'AssignmentPattern':
+      return true
+    case 'ObjectPattern':
+    case 'ArrayPattern':
+      return isInDestructureAssignment(parent, parentStack)
+  }
+
+  return false
+}
+
+export function isInDestructureAssignment(
+  parent: Node,
+  parentStack: Node[]
+): boolean {
+  if (
+    parent &&
+    (parent.type === 'ObjectProperty' || parent.type === 'ArrayPattern')
+  ) {
+    let i = parentStack.length
+    while (i--) {
+      const p = parentStack[i]
+      if (p.type === 'AssignmentExpression') {
+        return true
+      } else if (p.type !== 'ObjectProperty' && !p.type.endsWith('Pattern')) {
+        break
+      }
+    }
+  }
+  return false
+}
+
+function extractIdentifiers(
+  param: Node,
+  nodes: Identifier[] = []
+): Identifier[] {
+  switch (param.type) {
+    case 'Identifier':
+      nodes.push(param)
+      break
+
+    case 'MemberExpression':
+      let object: any = param
+      while (object.type === 'MemberExpression') {
+        object = object.object
+      }
+      nodes.push(object)
+      break
+
+    case 'ObjectPattern':
+      param.properties.forEach(prop => {
+        if (prop.type === 'RestElement') {
+          extractIdentifiers(prop.argument, nodes)
+        } else {
+          extractIdentifiers(prop.value, nodes)
+        }
+      })
+      break
+
+    case 'ArrayPattern':
+      param.elements.forEach(element => {
+        if (element) extractIdentifiers(element, nodes)
+      })
+      break
+
+    case 'RestElement':
+      extractIdentifiers(param.argument, nodes)
+      break
+
+    case 'AssignmentPattern':
+      extractIdentifiers(param.left, nodes)
+      break
+  }
+
+  return nodes
+}
+
+function markScopeIdentifier(
+  node: Node & { scopeIds?: Set<string> },
+  child: Identifier,
+  knownIds: Record<string, number>
+) {
+  const { name } = child
+  if (node.scopeIds && node.scopeIds.has(name)) {
+    return
+  }
+  if (name in knownIds) {
+    knownIds[name]++
+  } else {
+    knownIds[name] = 1
+  }
+  ;(node.scopeIds || (node.scopeIds = new Set())).add(name)
+}
+
+export const isFunctionType = (node: Node): node is Function => {
+  return /Function(?:Expression|Declaration)$|Method$/.test(node.type)
+}
+
+export const isStaticProperty = (node: Node): node is ObjectProperty =>
+  node &&
+  (node.type === 'ObjectProperty' || node.type === 'ObjectMethod') &&
+  !node.computed
+
+export const isStaticPropertyKey = (node: Node, parent: Node) =>
+  isStaticProperty(parent) && parent.key === node

packages/compiler-core/src/index.ts

@@ -31,6 +31,7 @@ export {
 
 export * from './ast'
 export * from './utils'
+export * from './babelUtils'
 export * from './runtimeHelpers'
 
 export { getBaseTransformPreset, TransformPreset } from './compile'