diff --git a/chapter4/node-serial-benchmark/package-lock.json b/chapter4/node-serial-benchmark/package-lock.json
index 5a04235..e6f9557 100644
--- a/chapter4/node-serial-benchmark/package-lock.json
+++ b/chapter4/node-serial-benchmark/package-lock.json
@@ -5,9 +5,9 @@
   "requires": true,
   "dependencies": {
     "acorn": {
-      "version": "5.7.3",
-      "resolved": "https://registry.npm.taobao.org/acorn/download/acorn-5.7.3.tgz?cache=0&other_urls=https%3A%2F%2Fregistry.npm.taobao.org%2Facorn%2Fdownload%2Facorn-5.7.3.tgz",
-      "integrity": "sha1-Z6ojG/iBKXS4UjWpZ3Hra9B+onk="
+      "version": "5.7.4",
+      "resolved": "https://registry.npmjs.org/acorn/-/acorn-5.7.4.tgz",
+      "integrity": "sha512-1D++VG7BhrtvQpNbBzovKNc1FLGGEE/oGe7b9xJm/RFHMBeUaUGpluV9RLjZa47YFdPcDAenEYuq9pQPcMdLJg=="
     },
     "ansi-regex": {
       "version": "2.1.1",