perf(util-endpoints): replace conditional spreads with direct assignment in evaluateEndpointRule

Author: trivikr

.changeset/nasty-beers-invite.md

@@ -2,4 +2,4 @@
 "@smithy/util-endpoints": patch
 ---
 
-Reduce allocations in evaluateCondition(s)
+Reduce temporary object allocations

packages/util-endpoints/src/utils/evaluateEndpointRule.ts

@@ -27,13 +27,13 @@ export const evaluateEndpointRule = (
 
   options.logger?.debug?.(`${debugId} Resolving endpoint from template: ${toDebugString(endpoint)}`);
 
-  return {
-    ...(headers != undefined && {
-      headers: getEndpointHeaders(headers, endpointRuleOptions),
-    }),
-    ...(properties != undefined && {
-      properties: getEndpointProperties(properties, endpointRuleOptions),
-    }),
-    url: getEndpointUrl(url, endpointRuleOptions),
-  };
+  const endpointToReturn: EndpointV2 = { url: getEndpointUrl(url, endpointRuleOptions) };
+  if (headers != undefined) {
+    endpointToReturn.headers = getEndpointHeaders(headers, endpointRuleOptions);
+  }
+  if (properties != undefined) {
+    endpointToReturn.properties = getEndpointProperties(properties, endpointRuleOptions);
+  }
+
+  return endpointToReturn;
 };