From 6746b1905e1669a68738563ab23ade1c6a3b25be Mon Sep 17 00:00:00 2001
From: Marijn Haverbeke <marijn@haverbeke.nl>
Date: Wed, 11 Nov 2020 17:54:26 +0100
Subject: [PATCH] Use Object.create where appropriate

This breaks support on ancient Node and IE versions, but at this point
that's okay (IE11 has Object.create).

Closes #992
---
 acorn-walk/src/index.js | 9 +--------
 acorn/src/expression.js | 2 +-
 acorn/src/state.js      | 2 +-
 3 files changed, 3 insertions(+), 10 deletions(-)

diff --git a/acorn-walk/src/index.js b/acorn-walk/src/index.js
index 2a044b7df..38e6159b3 100644
--- a/acorn-walk/src/index.js
+++ b/acorn-walk/src/index.js
@@ -164,17 +164,10 @@ export function findNodeBefore(node, pos, test, baseVisitor, state) {
   return max
 }
 
-// Fallback to an Object.create polyfill for older environments.
-const create = Object.create || function(proto) {
-  function Ctor() {}
-  Ctor.prototype = proto
-  return new Ctor
-}
-
 // Used to create a custom walker. Will fill in all missing node
 // type properties with the defaults.
 export function make(funcs, baseVisitor) {
-  let visitor = create(baseVisitor || base)
+  let visitor = Object.create(baseVisitor || base)
   for (let type in funcs) visitor[type] = funcs[type]
   return visitor
 }
diff --git a/acorn/src/expression.js b/acorn/src/expression.js
index f1e4f5811..819083a65 100644
--- a/acorn/src/expression.js
+++ b/acorn/src/expression.js
@@ -924,7 +924,7 @@ pp.isSimpleParamList = function(params) {
 // or "arguments" and duplicate parameters.
 
 pp.checkParams = function(node, allowDuplicates) {
-  let nameHash = {}
+  let nameHash = Object.create(null)
   for (let param of node.params)
     this.checkLValInnerPattern(param, BIND_VAR, allowDuplicates ? null : nameHash)
 }
diff --git a/acorn/src/state.js b/acorn/src/state.js
index f7e4700e2..1495ea17d 100644
--- a/acorn/src/state.js
+++ b/acorn/src/state.js
@@ -71,7 +71,7 @@ export class Parser {
     // Labels in scope.
     this.labels = []
     // Thus-far undefined exports.
-    this.undefinedExports = {}
+    this.undefinedExports = Object.create(null)
 
     // If enabled, skip leading hashbang line.
     if (this.pos === 0 && options.allowHashBang && this.input.slice(0, 2) === "#!")