Fix Lottie replay for Next builds and fallback sources

compiler/src/capture/lottie.ts

@@ -89,6 +89,13 @@ export async function captureLotties(
             if (!u || typeof u !== "string") return null;
             try { return new URL(u, document.baseURI).href; } catch { return null; }
           };
+          const registrySrc = (path: string, fileName: string): string | null => {
+            if (!path) return null;
+            if (/\.json(?:[?#]|$)/i.test(path)) return abs(path);
+            if (!fileName) return null;
+            const base = path.endsWith("/") ? path : path + "/";
+            return abs(base + (fileName.includes(".") ? fileName : fileName + ".json"));
+          };
           // climb to the nearest ancestor (or self) carrying a data-cid-cap
           const capOf = (node: Element | null): string | null => {
             let el: Element | null = node;
@@ -144,10 +151,12 @@ export async function captureLotties(
               // fall back to the in-memory animationData document.
               const path = (a.path as string) || "";
               const fileName = (a.fileName as string) || "";
-              let src: string | null = null;
-              if (path) src = abs(path.endsWith("/") || !fileName ? path + (fileName.endsWith(".json") ? fileName : "data.json") : path + (fileName ? (fileName.includes(".") ? fileName : fileName + ".json") : ""));
-              let inlineKey: string | null = null;
-              if (!src && a.animationData) inlineKey = stashInline(a.animationData);
+              const src = registrySrc(path, fileName);
+              // Keep in-memory data as a fallback even when the registry reports a URL:
+              // some sites expose only a directory-ish path, and guessed `data.json`
+              // URLs 404. Generation prefers a downloaded local path, then falls back
+              // to this JSON if the URL is absent or unreachable.
+              const inlineKey = a.animationData ? stashInline(a.animationData) : null;
               const rendererType = ((a.renderer as { rendererType?: string })?.rendererType)
                 || (a.renderer && a.renderer.constructor && a.renderer.constructor.name === "CanvasRenderer" ? "canvas" : undefined);
               push({ container, via: "registry", src, inlineKey, renderer: rendererType, loop: a.loop, autoplay: a.autoplay });

compiler/src/generate/lottie.ts

@@ -108,7 +108,6 @@ export function lottieWireJsx(spec: LottieSpec, indent: number): string {
 
 export const DITTO_LOTTIE_TSX = `"use client";
 import { useEffect } from "react";
-import lottie from "lottie-web";
 
 type RTLottie = {
   cid: string;
@@ -127,7 +126,11 @@ const byCid = (cid: string): HTMLElement | null => document.querySelector('[data
 export default function DittoLottie({ spec }: { spec: LottieSpec }) {
   useEffect(() => {
     const stopped = (window as any).__dittoMotionStopped === true;
-    const anims: Array<ReturnType<typeof lottie.loadAnimation>> = [];
+    const anims: Array<{ destroy: () => void; goToAndStop: (value: number, isFrame?: boolean) => void }> = [];
+    let cancelled = false;
+    void (async () => {
+      const lottie = (await import("lottie-web")).default;
+      if (cancelled) return;
       for (const it of spec.items) {
         const el = byCid(it.cid);
         if (!el) continue;
@@ -148,7 +151,8 @@ export default function DittoLottie({ spec }: { spec: LottieSpec }) {
           /* a single bad animation must not break the page */
         }
       }
-    return () => { for (const a of anims) { try { a.destroy(); } catch {} } };
+    })().catch(() => {});
+    return () => { cancelled = true; for (const a of anims) { try { a.destroy(); } catch {} } };
   }, [spec]);
   return null;
 }

compiler/test/lottie.test.ts

@@ -62,6 +62,20 @@ describe("buildLottieSpec", () => {
     assert.equal(spec.items[0]!.renderer, "canvas");
   });
 
+  it("falls back to inline animationData when a source URL was detected but not downloaded", () => {
+    const ir = irWith(node("n0", {}, [node("n6", { "data-cid-cap": "cap-1" })]));
+    const motion = emptyMotion({
+      lotties: [lottie({ src: "https://x/missing.json", inlineKey: "k0" })],
+      lottieInline: { k0: { v: "5.7", layers: [] } },
+    });
+    const graph: AssetGraph = { entries: [], byUrl: new Map() };
+
+    const spec = buildLottieSpec(ir, motion, graph);
+    assert.equal(spec.items.length, 1);
+    assert.equal(spec.items[0]!.path, null);
+    assert.deepEqual(spec.items[0]!.animationData, { v: "5.7", layers: [] });
+  });
+
   it("drops a lottie whose container node didn't survive into the IR", () => {
     const ir = irWith(node("n0", {}, [node("n6", { "data-cid-cap": "other-cap" })]));
     const motion = emptyMotion({ lotties: [lottie({ src: "https://x/anim.json" })] });