165 support incomplete url parsing for links (#167)

* Replace the URLs of unterminated links to prevent clicks

* Create full-mirrors-lead.md

Author: haydenbleasel

.changeset/full-mirrors-lead.md

@@ -0,0 +1,5 @@
+---
+"streamdown": patch
+---
+
+Support incomplete URL parsing for links

packages/streamdown/__tests__/parse-incomplete-markdown.test.ts

@@ -497,22 +497,20 @@ describe("parseIncompleteMarkdown", () => {
       );
     });
 
-    it("should handle partial link at chunk boundary", () => {
+    it("should handle partial link at chunk boundary - #165", () => {
       expect(parseIncompleteMarkdown("Check out [this lin")).toBe(
         "Check out [this lin](streamdown:incomplete-link)"
       );
-      // Links with partial URLs are kept as-is since they might be complete
+      // Links with partial URLs should now be completed with placeholder
       expect(parseIncompleteMarkdown("Visit [our site](https://exa")).toBe(
-        "Visit [our site](https://exa"
+        "Visit [our site](streamdown:incomplete-link)"
       );
     });
 
     it("should handle partial image at chunk boundary", () => {
       expect(parseIncompleteMarkdown("See ![the diag")).toBe("See ");
-      // Images with partial URLs are kept as-is since they might be complete
-      expect(parseIncompleteMarkdown("![logo](./assets/log")).toBe(
-        "![logo](./assets/log"
-      );
+      // Images with partial URLs should be removed (images can't show skeleton)
+      expect(parseIncompleteMarkdown("![logo](./assets/log")).toBe("");
     });
 
     it("should handle nested formatting cut mid-stream", () => {

packages/streamdown/lib/parse-incomplete-markdown.ts

@@ -17,6 +17,32 @@ const hasCompleteCodeBlock = (text: string): boolean => {
 
 // Handles incomplete links and images by preserving them with a special marker
 const handleIncompleteLinksAndImages = (text: string): string => {
+  // First check for incomplete URLs: [text](partial-url or ![text](partial-url without closing )
+  // Pattern: !?[text](url-without-closing-paren at end of string
+  const incompleteLinkUrlPattern = /(!?)\[([^\]]+)\]\(([^)]+)$/;
+  const incompleteLinkUrlMatch = text.match(incompleteLinkUrlPattern);
+
+  if (incompleteLinkUrlMatch) {
+    const isImage = incompleteLinkUrlMatch[1] === "!";
+    const linkText = incompleteLinkUrlMatch[2];
+    const partialUrl = incompleteLinkUrlMatch[3];
+
+    // Find the start position of this link/image pattern
+    const matchStart = text.lastIndexOf(
+      `${isImage ? "!" : ""}[${linkText}](${partialUrl}`
+    );
+    const beforeLink = text.substring(0, matchStart);
+
+    if (isImage) {
+      // For images with incomplete URLs, remove them entirely
+      return beforeLink;
+    }
+
+    // For links with incomplete URLs, replace the URL with placeholder and close it
+    return `${beforeLink}[${linkText}](streamdown:incomplete-link)`;
+  }
+
+  // Then check for incomplete link text: [partial-text without closing ]
   const linkMatch = text.match(linkImagePattern);
 
   if (linkMatch) {