diff --git a/package.json b/package.json
index a54e7d3..24832bd 100644
--- a/package.json
+++ b/package.json
@@ -29,7 +29,8 @@
     "check-typescript": "tsc",
     "prepublishOnly": "npm run build",
     "prettier": "prettier --write 'src/*.@(js|ts|tsx|json|css)'",
-    "link-dev": "./link-dev.sh"
+    "link-dev": "./link-dev.sh",
+    "check": "npm i && npm run prettier && npm run lint && tsc && npm run test"
   },
   "repository": {
     "type": "git",
diff --git a/src/getFlagsProxy.test.ts b/src/getFlagsProxy.test.ts
index a12bfab..04aa638 100644
--- a/src/getFlagsProxy.test.ts
+++ b/src/getFlagsProxy.test.ts
@@ -2,11 +2,6 @@ import { LDClient, LDFlagSet } from 'launchdarkly-js-client-sdk';
 import getFlagsProxy from './getFlagsProxy';
 import { defaultReactOptions } from './types';
 
-// tslint:disable-next-line: no-unsafe-any
-const variation = jest.fn((k: string): string | undefined => rawFlags[k]);
-
-const ldClient = ({ variation } as unknown) as LDClient;
-
 const rawFlags: LDFlagSet = {
   'foo-bar': 'foobar',
   'baz-qux': 'bazqux',
@@ -17,8 +12,18 @@ const camelizedFlags: LDFlagSet = {
   bazQux: 'bazqux',
 };
 
+// cast as unknown first to be able to partially mock ldClient
+const ldClient = ({ variation: jest.fn((flagKey) => rawFlags[flagKey] as string) } as unknown) as LDClient;
+
 beforeEach(jest.clearAllMocks);
 
+test('native Object functions should be ignored', () => {
+  const { flags } = getFlagsProxy(ldClient, rawFlags);
+  flags.hasOwnProperty('fooBar');
+  flags.propertyIsEnumerable('bazQux');
+  expect(ldClient.variation).not.toHaveBeenCalled();
+});
+
 test('camel cases keys', () => {
   const { flags } = getFlagsProxy(ldClient, rawFlags);
 
@@ -31,12 +36,12 @@ test('does not camel cases keys', () => {
   expect(flags).toEqual(rawFlags);
 });
 
-test('proxy calls variation on flag read', () => {
+test('proxy calls ldClient.variation on flag read', () => {
   const { flags } = getFlagsProxy(ldClient, rawFlags);
 
   expect(flags.fooBar).toBe('foobar');
 
-  expect(variation).toHaveBeenCalledWith('foo-bar', 'foobar');
+  expect(ldClient.variation).toHaveBeenCalledWith('foo-bar', 'foobar');
 });
 
 test('returns flag key map', () => {
@@ -56,5 +61,5 @@ test('does not use proxy if option is false', () => {
 
   expect(flags['foo-bar']).toBe('foobar');
 
-  expect(variation).not.toHaveBeenCalled();
+  expect(ldClient.variation).not.toHaveBeenCalled();
 });
diff --git a/src/getFlagsProxy.ts b/src/getFlagsProxy.ts
index 22c6ac4..409676a 100644
--- a/src/getFlagsProxy.ts
+++ b/src/getFlagsProxy.ts
@@ -58,17 +58,19 @@ function toFlagsProxy(ldClient: LDClient, flags: LDFlagSet, flagKeyMap: LDFlagKe
     // trap for reading a flag value using `LDClient#variation` to trigger an evaluation event
     get(target, prop, receiver) {
       const currentValue = Reflect.get(target, prop, receiver);
-      if (typeof prop === 'symbol') {
+
+      // only process flag keys and ignore symbols and native Object functions
+      if (typeof prop === 'symbol' || !hasFlag(flagKeyMap, prop)) {
         return currentValue;
       }
+
       if (currentValue === undefined) {
         return;
       }
-      const originalFlagKey = hasFlag(flagKeyMap, prop) ? flagKeyMap[prop] : prop;
-      const nextValue = ldClient.variation(originalFlagKey, currentValue);
 
-      return nextValue;
+      return ldClient.variation(flagKeyMap[prop], currentValue);
     },
+
     // disable all mutation functions to make proxy readonly
     setPrototypeOf: () => false,
     set: () => false,