fix: table section tags should implicitly close other table sections

Opening a <thead>, <tbody>, or <tfoot> should auto-close any currently
open table section, including the row and cell elements on top of it.
Previously <tfoot> was missing from the close set, and <thead> had no
entry at all, so a <tbody> after <tfoot> (or <thead> after <tbody>)
would nest incorrectly instead of being siblings under <table>.

Expanded tableSectionTags to include tr, td, and th so the top-of-stack
close loop can peel off row/cell elements to reach the section beneath.

Ref: https://html.spec.whatwg.org/multipage/syntax.html#optional-tags

Author: vimzh

src/Parser.spec.ts

@@ -179,6 +179,43 @@ describe("API", () => {
         p.write("<__proto__>");
     });
 
+    it("should implicitly close table sections when another section opens", () => {
+        const onopentagname = vi.fn();
+        const onclosetag = vi.fn();
+
+        // <tbody> must auto-close <tfoot>
+        new Parser({ onopentagname, onclosetag }).end(
+            "<table><tfoot><tr><td>F<tbody><tr><td>B</table>",
+        );
+
+        expect(onclosetag).toHaveBeenCalledWith("tfoot", true);
+        const tfootClose = onclosetag.mock.calls.findIndex(
+            ([name]: [string]) => name === "tfoot",
+        );
+        const tbodyOpen = onopentagname.mock.calls.findIndex(
+            ([name]: [string]) => name === "tbody",
+        );
+        expect(tfootClose).toBeLessThan(tbodyOpen);
+    });
+
+    it("should implicitly close <tbody> when <thead> opens", () => {
+        const onopentagname = vi.fn();
+        const onclosetag = vi.fn();
+
+        new Parser({ onopentagname, onclosetag }).end(
+            "<table><tbody><tr><td>B<thead><tr><th>H</table>",
+        );
+
+        expect(onclosetag).toHaveBeenCalledWith("tbody", true);
+        const tbodyClose = onclosetag.mock.calls.findIndex(
+            ([name]: [string]) => name === "tbody",
+        );
+        const theadOpen = onopentagname.mock.calls.findIndex(
+            ([name]: [string]) => name === "thead",
+        );
+        expect(tbodyClose).toBeLessThan(theadOpen);
+    });
+
     it("should support custom tokenizer", () => {
         class CustomTokenizer extends Tokenizer {}
 

src/Parser.ts

@@ -13,7 +13,7 @@ const formTags = new Set([
 ]);
 const pTag = new Set(["p"]);
 const headingTags = new Set(["h1", "h2", "h3", "h4", "h5", "h6", "p"]);
-const tableSectionTags = new Set(["thead", "tbody"]);
+const tableSectionTags = new Set(["thead", "tbody", "tfoot", "tr", "td", "th"]);
 const ddtTags = new Set(["dd", "dt"]);
 const rtpTags = new Set(["rt", "rp"]);
 
@@ -64,6 +64,7 @@ const openImpliesClose = new Map<string, Set<string>>([
     ["ul", pTag],
     ["rt", rtpTags],
     ["rp", rtpTags],
+    ["thead", tableSectionTags],
     ["tbody", tableSectionTags],
     ["tfoot", tableSectionTags],
 ]);