perf(external_link): optimize external link filter

lib/plugins/filter/after_render/external_link.ts

@@ -1,12 +1,16 @@
 import { isExternalLink } from 'hexo-util';
-import Hexo from '../../../hexo';
+import type Hexo from '../../../hexo';
 
 let EXTERNAL_LINK_SITE_ENABLED = true;
 const rATag = /<a(?:\s+?|\s+?[^<>]+?\s+?)href=["']((?:https?:|\/\/)[^<>"']+)["'][^<>]*>/gi;
 const rTargetAttr = /target=/i;
 const rRelAttr = /rel=/i;
 const rRelStrAttr = /rel=["']([^<>"']*)["']/i;
 
+const addNoopener = (relStr: string, rel: string) => {
+  return rel.includes('noopenner') ? relStr : `rel="${rel} noopener"`;
+};
+
 function externalLinkFilter(this: Hexo, data: string): string {
   if (!EXTERNAL_LINK_SITE_ENABLED) return;
 
@@ -17,18 +21,30 @@ function externalLinkFilter(this: Hexo, data: string): string {
     return;
   }
 
-  return data.replace(rATag, (str, href) => {
-    if (!isExternalLink(href, url, external_link.exclude as any) || rTargetAttr.test(str)) return str;
+  let result = '';
+  let lastIndex = 0;
+  let match;
+
+  while ((match = rATag.exec(data)) !== null) {
+    result += data.slice(lastIndex, match.index);
 
-    if (rRelAttr.test(str)) {
-      str = str.replace(rRelStrAttr, (relStr, rel) => {
-        return rel.includes('noopenner') ? relStr : `rel="${rel} noopener"`;
-      });
-      return str.replace('href=', 'target="_blank" href=');
+    const str = match[0];
+    const href = match[1];
+
+    if (!isExternalLink(href, url, external_link.exclude as any) || rTargetAttr.test(str)) {
+      result += str;
+    } else {
+      if (rRelAttr.test(str)) {
+        result += str.replace(rRelStrAttr, addNoopener).replace('href=', 'target="_blank" href=');
+      } else {
+        result += str.replace('href=', 'target="_blank" rel="noopener" href=');
+      }
     }
+    lastIndex = rATag.lastIndex;
+  }
+  result += data.slice(lastIndex);
 
-    return str.replace('href=', 'target="_blank" rel="noopener" href=');
-  });
+  return result;
 }
 
 export = externalLinkFilter;