perf: improve ETag match loop

closes #22

Author: billouboq

HISTORY.md

@@ -2,6 +2,7 @@ unreleased
 ==========
 
   * Fix handling of modified headers with invalid dates
+  * perf: improve ETag match loop
 
 0.5.0 / 2017-02-21
 ==================

index.js

@@ -58,13 +58,18 @@ function fresh (reqHeaders, resHeaders) {
   // if-none-match
   if (noneMatch && noneMatch !== '*') {
     var etag = resHeaders['etag']
-    var etagStale = !etag || noneMatch.split(TOKEN_LIST_REGEXP).every(function (match) {
-      return match !== etag && match !== 'W/' + etag && 'W/' + match !== etag
-    })
 
-    if (etagStale) {
+    if (!etag) {
       return false
     }
+
+    var matches = noneMatch.split(TOKEN_LIST_REGEXP)
+    for (var i = 0; i < matches.length; i++) {
+      var match = matches[i]
+      if (match !== etag && match !== 'W/' + etag && 'W/' + match !== etag) {
+        return false
+      }
+    }
   }
 
   // if-modified-since