fix(preload): resolve anchor hrefs against document.baseURI

.changeset/template-anchor-url.md

@@ -0,0 +1,5 @@
+---
+"@solidjs/router": patch
+---
+
+Link preloading and click handling resolve an anchor's `href` against `document.baseURI`. An anchor cloned from a `<template>` keeps its raw `href` (e.g. `/about`) until it is adopted into the page, so `eagerPreload`'s idle flush threw `Invalid URL` when it reached one that a transition still held off the page (#704).

src/data/events.ts

@@ -96,7 +96,8 @@ export function setupNativeEvents({
       const rel = (a.getAttribute("rel") || "").split(/\s+/);
       if (a.hasAttribute("download") || rel.includes("external")) return;
 
-      const url = svg ? new URL(href, document.baseURI) : new URL(href);
+      // a clone from a `<template>` keeps a raw `href` until it is adopted (#704)
+      const url = new URL(href, document.baseURI);
       // Skip non-http(s) schemes (blob:, mailto:, tel:, data:, ...). blob: URLs
       // inherit the page origin, so the origin check below won't reject them. #382
       if (url.protocol !== "https:" && url.protocol !== "http:") return;

test/data/events.spec.ts

@@ -1105,5 +1105,16 @@ describe("tap and ambient preload strategies", () => {
       vi.runAllTimers();
       expect(preloaded()).toEqual(["/b:false"]);
     });
+
+    test("an anchor cloned from a template preloads before it is adopted (#704)", () => {
+      mount(eagerPreload({ all: true }));
+      const t = document.createElement("template");
+      t.innerHTML = '<a href="/a">a</a>';
+      const a = t.content.firstChild!.cloneNode(true) as HTMLAnchorElement;
+      const disposeLink = createRoot(d => (claimElement(a), d));
+      expect(() => vi.runAllTimers()).not.toThrow();
+      expect(preloaded()).toEqual(["/a:false"]);
+      disposeLink();
+    });
   });
 });