From 5c69ad8e8bc8427321fd2c5364eb1e40658805f3 Mon Sep 17 00:00:00 2001
From: Pascal Hartig <realpassy@fb.com>
Date: Wed, 28 Aug 2019 03:00:15 -0700
Subject: [PATCH] Make LowPassFilter strict

Summary: Per title.

Reviewed By: danielbuechele

Differential Revision: D17073163

fbshipit-source-id: 08127d85af317ff701f4d131fd41df095f50f6a4
---
 src/utils/LowPassFilter.tsx | 10 +++++++++-
 1 file changed, 9 insertions(+), 1 deletion(-)

diff --git a/src/utils/LowPassFilter.tsx b/src/utils/LowPassFilter.tsx
index 8db8e4a7f..07331d37b 100644
--- a/src/utils/LowPassFilter.tsx
+++ b/src/utils/LowPassFilter.tsx
@@ -24,7 +24,15 @@ export default class LowPassFilter {
     let removed: number = 0;
 
     if (this.hasFullBuffer()) {
-      removed = this.buffer.shift();
+      const tmp: number | undefined = this.buffer.shift();
+
+      if (tmp === undefined) {
+        throw new Error(
+          'Invariant violation: Buffer reported full but shift returned nothing.',
+        );
+      }
+
+      removed = tmp;
     }
 
     this.buffer.push(value);