Function walk

packages/vite/src/node/ssr/ssrTransform.ts:452–641

* Same logic from \@vue/compiler-core & \@vue/compiler-sfc * Except this is using acorn AST

(
  root: ESTree.Node,
  { onIdentifier, onImportMeta, onDynamicImport, onStatements }: Visitors,
)

 * Except this is using acorn AST
 */
function walk(
  root: ESTree.Node,
  { onIdentifier, onImportMeta, onDynamicImport, onStatements }: Visitors,
) {
  const parentStack: ESTree.Node[] = []
  const varKindStack: ESTree.VariableDeclaration['kind'][] = []
  const scopeMap = new WeakMap<ESTree.Node, Set<string>>()
  const identifiers: [id: any, stack: ESTree.Node[]][] = []

  const setScope = (node: ESTree.Node, name: string) => {
    let scopeIds = scopeMap.get(node)
    if (scopeIds && scopeIds.has(name)) {
      return
    }
    if (!scopeIds) {
      scopeIds = new Set()
      scopeMap.set(node, scopeIds)
    }
    scopeIds.add(name)
  }

  function isInScope(name: string, parents: ESTree.Node[]) {
    return parents.some((node) => scopeMap.get(node)?.has(name))
  }
  function handlePattern(p: ESTree.ParamPattern, parentScope: ESTree.Node) {
    if (p.type === 'Identifier') {
      setScope(parentScope, p.name)
    } else if (p.type === 'RestElement') {
      handlePattern(p.argument, parentScope)
    } else if (p.type === 'ObjectPattern') {
      p.properties.forEach((property) => {
        if (property.type === 'RestElement') {
          setScope(
            parentScope,
            (property.argument as ESTree.IdentifierName).name,
          )
        } else {
          handlePattern(property.value, parentScope)
        }
      })
    } else if (p.type === 'ArrayPattern') {
      p.elements.forEach((element) => {
        if (element) {
          handlePattern(element, parentScope)
        }
      })
    } else if (p.type === 'AssignmentPattern') {
      handlePattern(p.left, parentScope)
    } else {
      setScope(parentScope, (p as any).name)
    }
  }

  ;(eswalk as any)(root, {
    enter(node: ESTree.Node, parent: ESTree.Node | null) {
      if (node.type === 'ImportDeclaration') {
        return this.skip()
      }