feat(core): Add support for creating Web ReadableStream from a file

ts/smartstream.nodewebhelpers.ts

@@ -0,0 +1,34 @@
+import { createReadStream } from 'fs';
+
+/**
+ * Creates a Web ReadableStream from a file.
+ *
+ * @param filePath - The path to the file to be read
+ * @returns A Web ReadableStream that reads the file in chunks
+ */
+export function createWebReadableStreamFromFile(filePath: string): ReadableStream<Uint8Array> {
+  const fileStream = createReadStream(filePath);
+
+  return new ReadableStream({
+    start(controller) {
+      // When data is available, enqueue it into the Web ReadableStream
+      fileStream.on('data', (chunk) => {
+        controller.enqueue(chunk as Uint8Array);
+      });
+
+      // When the file stream ends, close the Web ReadableStream
+      fileStream.on('end', () => {
+        controller.close();
+      });
+
+      // If there's an error, error the Web ReadableStream
+      fileStream.on('error', (err) => {
+        controller.error(err);
+      });
+    },
+    cancel() {
+      // If the Web ReadableStream is canceled, destroy the file stream
+      fileStream.destroy();
+    }
+  });
+}