fix: preserve literal HTML in Markdown table exports

.changeset/preserve-markdown-table-literals.md

@@ -0,0 +1,5 @@
+---
+"streamdown": patch
+---
+
+Preserve literal HTML tags and character entities when copying or downloading tables as Markdown.

packages/streamdown/__tests__/table-utils.test.ts

@@ -1,3 +1,4 @@
+import { marked } from "marked";
 import { beforeEach, describe, expect, it, vi } from "vitest";
 import {
   escapeMarkdownTableCell,
@@ -481,6 +482,26 @@ describe("Table Utils", () => {
   });
 
   describe("tableDataToMarkdown", () => {
+    it("should preserve literal HTML and entities when rendered again", () => {
+      const table = document.createElement("table");
+      table.innerHTML = `
+        <thead><tr><th>Type &lt;T&gt;</th><th>Entities</th></tr></thead>
+        <tbody><tr>
+          <td><code>Array&lt;string&gt;</code></td>
+          <td>&amp;copy; and &amp;#124;</td>
+        </tr></tbody>
+      `;
+      const data = extractTableDataFromElement(table);
+      const markdown = tableDataToMarkdown(data);
+      const container = document.createElement("div");
+      container.innerHTML = marked.parse(markdown, { async: false });
+      const restoredTable = container.querySelector(
+        "table"
+      ) as HTMLTableElement;
+
+      expect(extractTableDataFromElement(restoredTable)).toEqual(data);
+    });
+
     it("should convert simple table data to Markdown", () => {
       const data: TableData = {
         headers: ["Name", "Age", "City"],

packages/streamdown/lib/table/utils.ts

@@ -184,7 +184,14 @@ export const escapeMarkdownTableCell = (cell: string): string => {
   // OPTIMIZATION: Fast path for cells that don't need escaping - check chars directly
   let needsEscaping = false;
   for (const char of cell) {
-    if (char === "\\" || char === "|" || char === "\n") {
+    if (
+      char === "\\" ||
+      char === "|" ||
+      char === "\n" ||
+      char === "&" ||
+      char === "<" ||
+      char === ">"
+    ) {
       needsEscaping = true;
       break;
     }
@@ -202,6 +209,12 @@ export const escapeMarkdownTableCell = (cell: string): string => {
       parts.push("\\|");
     } else if (char === "\n") {
       parts.push("<br>");
+    } else if (char === "&") {
+      parts.push("&amp;");
+    } else if (char === "<") {
+      parts.push("&lt;");
+    } else if (char === ">") {
+      parts.push("&gt;");
     } else {
       parts.push(char);
     }