From e6b1df5de3ba853b187c738039b57f9b3372b758 Mon Sep 17 00:00:00 2001
From: Aleksei Androsov <aandrosov@yandex-team.ru>
Date: Tue, 17 Jan 2023 18:21:48 +0300
Subject: [PATCH] perf(propagator-jaeger): improve deserializeSpanContext
 performance

---
 CHANGELOG.md                                                | 2 ++
 .../opentelemetry-propagator-jaeger/src/JaegerPropagator.ts | 6 +++---
 2 files changed, 5 insertions(+), 3 deletions(-)

diff --git a/CHANGELOG.md b/CHANGELOG.md
index d6385594f3f..c2968bfeca2 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -11,6 +11,8 @@ For experimental package changes, see the [experimental CHANGELOG](experimental/
 
 ### :rocket: (Enhancement)
 
+* perf(propagator-jaeger): improve deserializeSpanContext performance [#3541](https://github.com/open-telemetry/opentelemetry-js/pull/3541) @doochik
+
 ### :bug: (Bug Fix)
 
 ### :books: (Refine Doc)
diff --git a/packages/opentelemetry-propagator-jaeger/src/JaegerPropagator.ts b/packages/opentelemetry-propagator-jaeger/src/JaegerPropagator.ts
index b4421e395b7..f6e2e8fc083 100644
--- a/packages/opentelemetry-propagator-jaeger/src/JaegerPropagator.ts
+++ b/packages/opentelemetry-propagator-jaeger/src/JaegerPropagator.ts
@@ -134,6 +134,8 @@ export class JaegerPropagator implements TextMapPropagator {
   }
 }
 
+const validHexRe = /^[0-9a-f]{1,2}$/i;
+
 /**
  * @param {string} serializedString - a serialized span context.
  * @return {SpanContext} - returns a span context represented by the serializedString.
@@ -148,9 +150,7 @@ function deserializeSpanContext(serializedString: string): SpanContext | null {
 
   const traceId = _traceId.padStart(32, '0');
   const spanId = _spanId.padStart(16, '0');
-  const traceFlags = flags.match(/^[0-9a-f]{1,2}$/i)
-    ? parseInt(flags, 16) & 1
-    : 1;
+  const traceFlags = validHexRe.test(flags) ? parseInt(flags, 16) & 1 : 1;
 
   return { traceId, spanId, isRemote: true, traceFlags };
 }