diff --git a/lib/core/package.json b/lib/core/package.json
index c5a66971c39..6be9fc9f34c 100644
--- a/lib/core/package.json
+++ b/lib/core/package.json
@@ -33,6 +33,7 @@
     "@babel/plugin-proposal-class-properties": "^7.8.3",
     "@babel/plugin-proposal-export-default-from": "^7.8.3",
     "@babel/plugin-proposal-object-rest-spread": "^7.9.6",
+    "@babel/plugin-proposal-private-methods": "^7.8.3",
     "@babel/plugin-syntax-dynamic-import": "^7.8.3",
     "@babel/plugin-transform-arrow-functions": "^7.8.3",
     "@babel/plugin-transform-block-scoping": "^7.8.3",
diff --git a/lib/core/src/server/common/babel.js b/lib/core/src/server/common/babel.js
index 10436d77ff8..84202a28327 100644
--- a/lib/core/src/server/common/babel.js
+++ b/lib/core/src/server/common/babel.js
@@ -2,6 +2,7 @@ export const plugins = [
   require.resolve('@babel/plugin-transform-shorthand-properties'),
   require.resolve('@babel/plugin-transform-block-scoping'),
   [require.resolve('@babel/plugin-proposal-class-properties'), { loose: true }],
+  [require.resolve('@babel/plugin-proposal-private-methods'), { loose: true }],
   require.resolve('@babel/plugin-proposal-export-default-from'),
   require.resolve('@babel/plugin-syntax-dynamic-import'),
   [
diff --git a/yarn.lock b/yarn.lock
index ee6785ff4c0..9eb577bb1c0 100644
--- a/yarn.lock
+++ b/yarn.lock
@@ -941,6 +941,14 @@
     "@babel/helper-plugin-utils" "^7.8.3"
     "@babel/plugin-syntax-optional-chaining" "^7.8.0"
 
+"@babel/plugin-proposal-private-methods@^7.8.3":
+  version "7.8.3"
+  resolved "https://registry.yarnpkg.com/@babel/plugin-proposal-private-methods/-/plugin-proposal-private-methods-7.8.3.tgz#01248c6c8dc292116b3b4ebd746150f4f0728bab"
+  integrity sha512-ysLAper960yy1TVXa2lMYdCQIGqtUXo8sVb+zYE7UTiZSLs6/wbZ0PrrXEKESJcK3SgFWrF8WpsaDzdslhuoZA==
+  dependencies:
+    "@babel/helper-create-class-features-plugin" "^7.8.3"
+    "@babel/helper-plugin-utils" "^7.8.3"
+
 "@babel/plugin-proposal-unicode-property-regex@^7.2.0", "@babel/plugin-proposal-unicode-property-regex@^7.4.4", "@babel/plugin-proposal-unicode-property-regex@^7.8.3":
   version "7.8.8"
   resolved "https://registry.yarnpkg.com/@babel/plugin-proposal-unicode-property-regex/-/plugin-proposal-unicode-property-regex-7.8.8.tgz#ee3a95e90cdc04fe8cd92ec3279fa017d68a0d1d"
@@ -29015,7 +29023,17 @@ send@^0.16.2:
     range-parser "~1.2.0"
     statuses "~1.4.0"
 
-serialize-javascript@^1.4.0, serialize-javascript@^2.1.2, serialize-javascript@^3.0.0:
+serialize-javascript@^1.4.0:
+  version "1.9.1"
+  resolved "https://registry.yarnpkg.com/serialize-javascript/-/serialize-javascript-1.9.1.tgz#cfc200aef77b600c47da9bb8149c943e798c2fdb"
+  integrity sha512-0Vb/54WJ6k5v8sSWN09S0ora+Hnr+cX40r9F170nT+mSkaxltoE/7R3OrIdBSUv1OoiobH1QoWQbCnAO+e8J1A==
+
+serialize-javascript@^2.1.2:
+  version "2.1.2"
+  resolved "https://registry.yarnpkg.com/serialize-javascript/-/serialize-javascript-2.1.2.tgz#ecec53b0e0317bdc95ef76ab7074b7384785fa61"
+  integrity sha512-rs9OggEUF0V4jUSecXazOYsLfu7OGK2qIn3c7IPBiffz32XniEp/TX9Xmc9LQfK2nQ2QKHvZ2oygKUGU0lG4jQ==
+
+serialize-javascript@^3.0.0:
   version "3.0.0"
   resolved "https://registry.yarnpkg.com/serialize-javascript/-/serialize-javascript-3.0.0.tgz#492e489a2d77b7b804ad391a5f5d97870952548e"
   integrity sha512-skZcHYw2vEX4bw90nAr2iTTsz6x2SrHEnfxgKYmZlvJYBEZrvbKtobJWlQ20zczKb3bsHHXXTYt48zBA7ni9cw==