diff --git a/packages/babel-plugin-inject-polyfills/src/index.js b/packages/babel-plugin-inject-polyfills/src/index.js
index 71b4e334..96601a42 100644
--- a/packages/babel-plugin-inject-polyfills/src/index.js
+++ b/packages/babel-plugin-inject-polyfills/src/index.js
@@ -29,12 +29,13 @@ import type {
   Targets,
   MetaDescriptor,
   PolyfillProvider,
+  Utils,
 } from "./types";
 
 import createMetaResolver from "./meta-resolver";
 
 export { resolveProvider } from "./config";
-export type { PolyfillProvider, MetaDescriptor };
+export type { PolyfillProvider, MetaDescriptor, Utils };
 
 export default declare((api, options: Options, dirname: string) => {
   api.assertVersion(7);
diff --git a/packages/babel-polyfill-provider-es-shims/src/index.js b/packages/babel-polyfill-provider-es-shims/src/index.js
index 4a8795eb..c0f1c0ed 100644
--- a/packages/babel-polyfill-provider-es-shims/src/index.js
+++ b/packages/babel-polyfill-provider-es-shims/src/index.js
@@ -1,6 +1,6 @@
 // @flow
 
-import { type PolyfillProvider } from "@babel/plugin-inject-polyfills";
+import type { PolyfillProvider, Utils } from "@babel/plugin-inject-polyfills";
 import resolve from "resolve";
 import debounce from "lodash.debounce";
 
@@ -43,7 +43,7 @@ export default ((
     }
   }
 
-  function createDescIterator(cb) {
+  function createDescIterator(cb: (Descriptor, Utils, Object) => void) {
     return (meta, utils, path) => {
       const resolved = resolvePolyfill(meta);
       if (!resolved) return;
diff --git a/packages/babel-polyfill-provider-es-shims/src/mappings.js b/packages/babel-polyfill-provider-es-shims/src/mappings.js
index cae07deb..c89d9cd4 100644
--- a/packages/babel-polyfill-provider-es-shims/src/mappings.js
+++ b/packages/babel-polyfill-provider-es-shims/src/mappings.js
@@ -1,5 +1,8 @@
 // @flow
 
+// $FlowIgnore
+const has = Function.call.bind(Object.hasOwnProperty);
+
 export type Descriptor = {
   name: string,
   version: string,
@@ -8,9 +11,9 @@ export type Descriptor = {
   global?: false,
 };
 
-export const Globals = Object.create(null);
-export const StaticProperties = Object.create(null);
-export const InstanceProperties = Object.create(null);
+export const Globals = {};
+export const StaticProperties = {};
+export const InstanceProperties = {};
 
 defineGlobal("globalThis", "1.0.0", "globalThis");
 
@@ -58,7 +61,7 @@ function defineGlobal(name, version, pkg) {
 }
 
 function defineStatic(object, property, version, pkg) {
-  if (!StaticProperties[object]) StaticProperties[object] = Object.create(null);
+  if (!has(StaticProperties, object)) StaticProperties[object] = {};
 
   StaticProperties[object][property] = [
     createDescriptor(`${object}.${property}`, version, pkg),
@@ -66,7 +69,7 @@ function defineStatic(object, property, version, pkg) {
 }
 
 function defineInstance(object, property, version, pkg) {
-  if (!InstanceProperties[property]) InstanceProperties[property] = [];
+  if (!has(InstanceProperties, property)) InstanceProperties[property] = [];
 
   InstanceProperties[property].push({
     ...createDescriptor(`${object}.prototype.${property}`, version, pkg),