fix: prevent double processing and fix H1-H6 header detection

- Fix elements being processed multiple times by excluding generated elements
- Fix H1-H6 headers incorrectly matching chemical patterns
- Add proper exclusion for sup.ss-sup and sub.ss-sub elements
- Centralize CSS_CLASSES constant for consistency

Author: aaronlippold

src/runtime/smartscript/config.ts

@@ -4,6 +4,18 @@
 
 import type { SuperscriptConfig } from './types'
 
+/**
+ * CSS class names used by SmartScript (not configurable)
+ */
+export const CSS_CLASSES = {
+  superscript: 'ss-sup',
+  subscript: 'ss-sub',
+  trademark: 'ss-tm',
+  registered: 'ss-reg',
+  ordinal: 'ss-ordinal',
+  math: 'ss-math',
+} as const
+
 /**
  * Default configuration values
  */
@@ -34,6 +46,9 @@ export const DEFAULT_CONFIG: SuperscriptConfig = {
       'style',
       '.no-superscript',
       '[data-no-superscript]',
+      // Exclude our own generated elements
+      'sup.ss-sup',
+      'sub.ss-sub',
     ],
   },
   performance: {

src/runtime/smartscript/dom.ts

@@ -4,6 +4,7 @@
 
 import type { TextPart } from './types'
 import { logger } from './logger'
+import { CSS_CLASSES } from './config'
 
 // Pre-compiled regex patterns for performance
 const DIGITS_ONLY = /^\d+$/
@@ -21,23 +22,23 @@ export function createSuperscriptElement(
 
   switch (type) {
     case 'trademark':
-      sup.className = 'ss-sup ss-tm'
+      sup.className = `${CSS_CLASSES.superscript} ${CSS_CLASSES.trademark}`
       sup.setAttribute('aria-label', 'trademark')
       break
     case 'registered':
-      sup.className = 'ss-sup ss-reg'
+      sup.className = `${CSS_CLASSES.superscript} ${CSS_CLASSES.registered}`
       sup.setAttribute('aria-label', 'registered')
       break
     case 'ordinal':
-      sup.className = 'ss-sup ss-ordinal'
+      sup.className = `${CSS_CLASSES.superscript} ${CSS_CLASSES.ordinal}`
       sup.setAttribute('aria-label', content)
       break
     case 'math':
-      sup.className = 'ss-sup ss-math'
+      sup.className = `${CSS_CLASSES.superscript} ${CSS_CLASSES.math}`
       sup.setAttribute('aria-label', `superscript ${content}`)
       break
     default:
-      sup.className = 'ss-sup'
+      sup.className = CSS_CLASSES.superscript
       sup.setAttribute('aria-label', `superscript ${content}`)
   }
 
@@ -53,7 +54,7 @@ export function createSubscriptElement(
 ): HTMLElement {
   const sub = document.createElement('sub')
   sub.textContent = content
-  sub.className = 'ss-sub'
+  sub.className = CSS_CLASSES.subscript
 
   switch (type) {
     case 'chemical':

src/runtime/smartscript/engine.ts

@@ -12,6 +12,7 @@ import {
   markAsProcessed,
   resetProcessingFlags,
 } from './dom'
+import { CSS_CLASSES } from './config'
 
 /**
  * Process a single text node
@@ -54,11 +55,11 @@ function createTextNodeFilter(
 ): NodeFilter {
   // Pre-compile exclude check for better performance
   const excludeSelectors = config.selectors.exclude
-  
+
   return {
     acceptNode: (node: Node): number => {
       const text = node.textContent
-      
+
       // Fast early exit for empty nodes
       if (!text || !text.trim()) {
         return NodeFilter.FILTER_REJECT
@@ -70,6 +71,14 @@ function createTextNodeFilter(
         return NodeFilter.FILTER_REJECT
       }
 
+      // Skip if parent is one of our generated elements
+      if (parent && (
+        (parent.tagName === 'SUP' && parent.classList.contains(CSS_CLASSES.superscript))
+        || (parent.tagName === 'SUB' && parent.classList.contains(CSS_CLASSES.subscript))
+      )) {
+        return NodeFilter.FILTER_REJECT
+      }
+
       // Use cached pattern check
       return needsProcessing(text, combinedPattern)
         ? NodeFilter.FILTER_ACCEPT
@@ -142,13 +151,13 @@ function batchProcessElements(
 
   function processBatch() {
     const endIndex = Math.min(index + batchSize, elements.length)
-    
+
     for (let i = index; i < endIndex; i++) {
       processElement(elements[i], config, patterns, combinedPattern)
     }
-    
+
     index = endIndex
-    
+
     if (index < elements.length) {
       // Process next batch in next frame
       requestAnimationFrame(processBatch)