fix(js): parse fragments in their insertion context

crates/obscura-dom/src/lib.rs

@@ -7,4 +7,4 @@ pub mod selector;
 pub mod serialize;
 
 pub use tree::{Attribute, DomTree, Node, NodeData, NodeId};
-pub use tree_sink::{parse_html, parse_fragment};
+pub use tree_sink::{parse_fragment, parse_fragment_with_context, parse_html};

crates/obscura-dom/src/tree_sink.rs

@@ -243,10 +243,14 @@ pub fn parse_html(html: &str) -> DomTree {
 }
 
 pub fn parse_fragment(html: &str) -> DomTree {
-    use html5ever::tendril::TendrilSink;
-    use html5ever::{parse_fragment, ParseOpts, QualName};
-
     let context_name = QualName::new(None, ns!(html), local_name!("body"));
+    parse_fragment_with_context(html, context_name)
+}
+
+pub fn parse_fragment_with_context(html: &str, context_name: QualName) -> DomTree {
+    use html5ever::tendril::TendrilSink;
+    use html5ever::{parse_fragment, ParseOpts};
+
     let tree = DomTree::new();
     parse_fragment(tree, ParseOpts::default(), context_name, vec![])
         .from_utf8()

crates/obscura-js/js/bootstrap.js

@@ -1227,44 +1227,20 @@ function _isSubmitButton(el) {
   return false;
 }
 
-// Ancestor chains required to parse table/select children, which the fragment
-// parser drops when parsed loosely (it uses a fixed <body> context). Each entry
-// is [openTags, closeTags, depth] — depth is how many lastChild hops reach the
-// container holding the parsed rows/cells/options. Classic jQuery wrapMap.
-const _wrapMap = {
-  option:   ['<select multiple="">', '</select>', 1],
-  optgroup: ['<select multiple="">', '</select>', 1],
-  tr:       ['<table><tbody>', '</tbody></table>', 2],
-  td:       ['<table><tbody><tr>', '</tr></tbody></table>', 3],
-  th:       ['<table><tbody><tr>', '</tr></tbody></table>', 3],
-  tbody:    ['<table>', '</table>', 1],
-  thead:    ['<table>', '</table>', 1],
-  tfoot:    ['<table>', '</table>', 1],
-  caption:  ['<table>', '</table>', 1],
-  colgroup: ['<table>', '</table>', 1],
-  col:      ['<table><colgroup>', '</colgroup></table>', 2],
-};
-// Parse an HTML string into an array of detached nodes. Table/select fragments
-// are wrapped in the required ancestor chain and dug back out so their children
-// survive; the wrapper is chosen from the fragment's own leading tag, falling
-// back to the insertion context element's tag.
-function _parseHTMLFragment(html, contextTag) {
+// Parse an HTML string into detached nodes using the actual insertion element
+// as html5ever's fragment context. This preserves table/select parsing rules,
+// comments, text-node order, and foreign-content namespaces without a wrap map.
+function _parseHTMLFragment(html, context) {
   html = String(html == null ? '' : html);
-  const m = /^\s*<\s*([a-zA-Z][a-zA-Z0-9]*)/.exec(html);
-  const lead = m ? m[1].toLowerCase() : '';
-  const key = _wrapMap[lead] ? lead : (contextTag ? String(contextTag).toLowerCase() : '');
-  const wrap = _wrapMap[key];
-  const tmp = document.createElement('div');
-  let container = tmp;
-  if (wrap) {
-    tmp.innerHTML = wrap[0] + html + wrap[1];
-    for (let d = 0; d < wrap[2]; d++) container = container.lastChild || container;
-  } else {
-    tmp.innerHTML = html;
-  }
+  const ns = context && context.nodeType === 1 ? context.namespaceURI : null;
+  const tag = context && context.nodeType === 1 ? context.localName : 'body';
+  const tmp = ns && ns !== 'http://www.w3.org/1999/xhtml'
+    ? document.createElementNS(ns, tag)
+    : document.createElement(tag);
+  tmp.innerHTML = html;
   const out = [];
   let child;
-  while ((child = container.firstChild)) out.push(container.removeChild(child));
+  while ((child = tmp.firstChild)) out.push(tmp.removeChild(child));
   return out;
 }
 
@@ -1526,23 +1502,21 @@ class Element extends Node {
     // table/select fragments keep the right parsing context (_parseHTMLFragment).
     const pos = String(position).toLowerCase();
     const parent = this.parentNode;
-    const contextTag = (pos === 'beforebegin' || pos === 'afterend')
-      ? (parent && parent.nodeType === 1 ? parent.tagName : 'body')
-      : this.tagName;
+    const context = (pos === 'beforebegin' || pos === 'afterend') ? parent : this;
     switch (pos) {
       case 'beforebegin':
-        if (parent) for (const n of _parseHTMLFragment(html, contextTag)) parent.insertBefore(n, this);
+        if (parent) for (const n of _parseHTMLFragment(html, context)) parent.insertBefore(n, this);
         break;
       case 'afterbegin': {
         const first = this.firstChild;
-        for (const n of _parseHTMLFragment(html, contextTag)) this.insertBefore(n, first);
+        for (const n of _parseHTMLFragment(html, context)) this.insertBefore(n, first);
         break;
       }
       case 'beforeend':
-        for (const n of _parseHTMLFragment(html, contextTag)) this.appendChild(n);
+        for (const n of _parseHTMLFragment(html, context)) this.appendChild(n);
         break;
       case 'afterend':
-        if (parent) { const next = this.nextSibling; for (const n of _parseHTMLFragment(html, contextTag)) parent.insertBefore(n, next); }
+        if (parent) { const next = this.nextSibling; for (const n of _parseHTMLFragment(html, context)) parent.insertBefore(n, next); }
         break;
       default:
         throw new DOMException(

crates/obscura-js/src/ops.rs

@@ -391,7 +391,16 @@ fn op_dom_inner(state: &OpState, cmd: String, arg1: String, arg2: String) -> Str
                 dom.detach(child);
             }
             if !arg2.is_empty() {
-                let fragment = obscura_dom::parse_fragment(&arg2);
+                let context_name = dom
+                    .with_node(target, |node| match &node.data {
+                        NodeData::Element { name, .. } => Some(name.clone()),
+                        _ => None,
+                    })
+                    .flatten();
+                let fragment = match context_name {
+                    Some(name) => obscura_dom::parse_fragment_with_context(&arg2, name),
+                    None => obscura_dom::parse_fragment(&arg2),
+                };
                 let import_root = fragment.find_body_or_root();
                 dom.import_children_from(target, &fragment, import_root);
             }

crates/obscura-js/src/runtime.rs

@@ -1346,6 +1346,32 @@ mod tests {
         assert_eq!(out, serde_json::json!("SyntaxError"));
     }
 
+    #[test]
+    fn insert_adjacent_html_keeps_leading_comments_in_table_contexts() {
+        let mut rt = setup_runtime(
+            r#"<html><body><table><tbody id="tb"><tr id="row"></tr></tbody></table></body></html>"#,
+        );
+        let out = rt
+            .evaluate(
+                "(function(){var tb=document.getElementById('tb');tb.insertAdjacentHTML('beforeend','<!--m--><tr><td>v</td></tr>');var row=document.getElementById('row');row.insertAdjacentHTML('beforeend','<!--n--><td>x</td>');return Array.from(tb.childNodes).map(function(n){return n.nodeName}).join('|')+';'+Array.from(row.childNodes).map(function(n){return n.nodeName}).join('|');})()",
+            )
+            .unwrap();
+        assert_eq!(out, serde_json::json!("TR|#comment|TR;#comment|TD"));
+    }
+
+    #[test]
+    fn insert_adjacent_html_uses_the_insertion_element_as_context() {
+        let mut rt = setup_runtime(
+            r#"<html><body><div id="d"></div><table id="table"><tbody id="tb"></tbody></table></body></html>"#,
+        );
+        let out = rt
+            .evaluate(
+                "(function(){var d=document.getElementById('d');d.insertAdjacentHTML('beforeend','<tr><td>v</td></tr>');var table=document.getElementById('table');table.insertAdjacentHTML('beforeend','<tr><td>x</td></tr>');var tb=document.getElementById('tb');tb.insertAdjacentHTML('beforeend','<tr><td>y</td></tr>tail');return d.firstChild.nodeName+':'+d.textContent+';'+table.lastElementChild.tagName+';'+Array.from(tb.childNodes).map(function(n){return n.nodeName+(n.data?':'+n.data:'')}).join('|');})()",
+            )
+            .unwrap();
+        assert_eq!(out, serde_json::json!("#text:v;TBODY;TR|#text:tail"));
+    }
+
     #[test]
     fn test_document_title() {
         let mut rt = setup_runtime("<html><head><title>Test</title></head><body></body></html>");