Add element.onEndTag js binding

js-api/Cargo.toml

@@ -2,7 +2,7 @@
 name = "lol-html"
 description = "Streaming HTML rewriter/parser with CSS selector-based API"
 license = "BSD-3-Clause"
-version = "2.1.1"
+version = "2.2.0"
 authors = ["Ivan Nikulin <[email protected]>", "Gus Caplan <[email protected]>"]
 repository = "https://github.com/cloudflare/lol-html"
 edition = "2021"

js-api/README.md

@@ -18,6 +18,10 @@ rewriter.on('a[href]', {
       .getAttribute('href')
       .replace('http:', 'https:');
     el.setAttribute('href', href);
+
+    el.onEndTag((tag)=> {
+      console.log(`Tag ended: ${tag.name}`);
+    });
   },
 });
 

js-api/src/element.rs

@@ -1,7 +1,32 @@
+use super::end_tag::EndTag;
 use super::*;
+use js_sys::Function as JsFunction;
 use lol_html::html_content::{Attribute as NativeAttribute, Element as NativeElement};
 use serde::Serialize;
 use serde_wasm_bindgen::to_value as to_js_value;
+use thiserror::Error;
+
+#[derive(Error, Debug)]
+#[error("JS handler error")]
+pub struct HandlerJsErrorWrap(pub JsValue);
+
+// SAFETY: The exposed js-api only supports single-threaded usage.
+unsafe impl Send for HandlerJsErrorWrap {}
+unsafe impl Sync for HandlerJsErrorWrap {}
+
+macro_rules! make_handler {
+    ($handler:ident, $JsArgType:ident, $typehint:ty) => {{
+        fn type_hint(h: $typehint) -> $typehint {
+            h
+        }
+        type_hint(Box::new(move |arg: &mut _| {
+            $JsArgType::with_native(arg, |js_value| $handler.call1(&JsValue::NULL, &js_value))
+                .map_err(|e| HandlerJsErrorWrap(e))?;
+
+            Ok(())
+        }))
+    }};
+}
 
 #[derive(Serialize)]
 pub struct Attribute {
@@ -112,4 +137,13 @@ impl Element {
     pub fn remove_and_keep_content(&mut self) -> Result<(), JsValue> {
         self.0.get_mut().map(|e| e.remove_and_keep_content())
     }
+
+    #[wasm_bindgen(method, js_name=onEndTag)]
+    pub fn on_end_tag(&mut self, handler: JsFunction) -> JsResult<()> {
+        if let Some(handlers) = self.0.get_mut()?.end_tag_handlers() {
+            handlers.push(make_handler!(handler, EndTag, lol_html::EndTagHandler));
+        }
+
+        Ok(())
+    }
 }

js-api/src/end_tag.rs

@@ -0,0 +1,16 @@
+use super::*;
+use lol_html::html_content::EndTag as NativeEndTag;
+
+#[wasm_bindgen]
+pub struct EndTag(NativeRefWrap<NativeEndTag<'static>>);
+
+impl_from_native!(NativeEndTag => EndTag);
+impl_mutations!(EndTag);
+
+#[wasm_bindgen]
+impl EndTag {
+    #[wasm_bindgen(getter)]
+    pub fn name(&self) -> JsResult<String> {
+        self.0.get().map(|d| d.name())
+    }
+}

js-api/src/lib.rs

@@ -171,6 +171,7 @@ mod comment;
 mod doctype;
 mod document_end;
 mod element;
+mod end_tag;
 mod handlers;
 mod html_rewriter;
 mod text_chunk;

js-api/test.js

@@ -7,12 +7,17 @@ const rewriter = new HTMLRewriter('utf8', (chunk) => {
   chunks.push(chunk);
 });
 
+const endTags = [];
 rewriter.on('a[href]', {
   element(el) {
     const href = el
       .getAttribute('href')
       .replace('http:', 'https:');
     el.setAttribute('href', href);
+
+    el.onEndTag((tag) => {
+      endTags.push(tag.name);
+    });
   },
 });
 
@@ -30,3 +35,7 @@ const output = Buffer.concat(chunks).toString('utf8');
 if (output != '<div><a href="https://example.com"></a></div>') {
   throw "fail";
 }
+
+if (endTags.length != 1 || endTags[0] != 'a') {
+  throw "onEndTag fail";
+}

src/rewritable_units/tokens/end_tag.rs

@@ -141,6 +141,13 @@ impl<'i> EndTag<'i> {
         self.mutations.mutate().remove();
     }
 
+    /// Returns `true` if the comment has been replaced or removed.
+    #[inline]
+    #[must_use]
+    pub fn removed(&self) -> bool {
+        self.mutations.removed()
+    }
+
     #[inline]
     fn serialize_self(&self, output_handler: &mut dyn FnMut(&[u8])) -> Result<(), RewritingError> {
         if let Some(raw) = &self.raw {