fix(web): do not rely on ReadableStream.from or new ReadableStream

src/platform.web.ts

@@ -2,9 +2,44 @@ import d from "https://cdn.skypack.dev/[email protected]";
 export { d as debug };
 
 // === Export system-specific operations
+async function writeAsyncItrToStream<T>(
+    itr: AsyncIterable<T>,
+    writer: WritableStreamDefaultWriter<T>,
+) {
+    let writeOrCloseErr;
+    let isWriteDone = false;
+    try {
+        for await (const chunk of itr) {
+            await writer.write(chunk);
+        }
+        isWriteDone = true;
+        await writer.close();
+    } catch (err) {
+        console.error(
+            `${isWriteDone ? "Stream error:" : "Chunk error:"} ${err}`,
+        );
+        writeOrCloseErr = err;
+    }
+    if (writeOrCloseErr) {
+        try {
+            await writer.abort(writeOrCloseErr);
+        } catch (err) {
+            console.error(`Abort error: ${err}`);
+        }
+    }
+}
+
 // Turn an AsyncIterable<Uint8Array> into a stream
-export const itrToStream = (itr: AsyncIterable<Uint8Array>) =>
-    ReadableStream.from(itr);
+export const itrToStream = (itr: AsyncIterable<Uint8Array>) => {
+    // do not assume ReadableStream.from or new ReadableStream to exist yet
+    const { readable, writable } = new TransformStream();
+    const writer = writable.getWriter();
+
+    // This should never throw
+    writeAsyncItrToStream(itr, writer);
+
+    return readable;
+};
 
 // === Base configuration for `fetch` calls
 export const baseFetchConfig = (_apiRoot: string) => ({});