From 13968c20d8514249336114fb29e2d28ce3effc37 Mon Sep 17 00:00:00 2001
From: Timothy Younger <timothy.younger@aexp.com>
Date: Tue, 17 Aug 2021 16:08:03 -0700
Subject: [PATCH] fix: throws helpful error instead of trying to call
 `Array.prototype.filter` on `undefined`

---
 src/index.js | 4 ++++
 src/test.js  | 7 +++++++
 2 files changed, 11 insertions(+)

diff --git a/src/index.js b/src/index.js
index dde47b3..8ee93ca 100644
--- a/src/index.js
+++ b/src/index.js
@@ -36,6 +36,10 @@ export class Flags extends Component {
     return (
       <FeatureFlags.Consumer>
         {(flags) => {
+          if (!Array.isArray(flags)) {
+            throw new Error('You should not use <Flags> outside a <FlagsProvider>');
+          }
+
           const matchingFlags = this.matchingFlags(flags);
           if (exactFlags) {
             return matchingFlags.length === authorizedFlags.length
diff --git a/src/test.js b/src/test.js
index b4b4914..10bd9ff 100644
--- a/src/test.js
+++ b/src/test.js
@@ -176,6 +176,13 @@ describe('Flags', () => {
       expect(result).toEqual(<h1>renderOn props</h1>);
     })
   })
+
+  describe('without context', () => {
+    it('without FlagsProvider or context', () => {
+      return expect(() => mount(<Flags authorizedFlags={[]} />))
+        .toThrow('You should not use <Flags> outside a <FlagsProvider>')
+    })
+  })
 })
 
 describe('FlagsProvider', () => {