Create fetchsse.js

fetchsse.js

@@ -0,0 +1,64 @@
+async function* streamAsyncIterable(stream) {
+    const reader = stream.getReader();
+    try {
+      while (true) {
+        const { done, value } = await reader.read();
+        if (done) {
+          return;
+        }
+        yield value;
+      }
+    } finally {
+      reader.releaseLock();
+    }
+  }
+
+// add timeout to fetchSSE
+async function fetchSSE(url, options, fetch2 = fetch) {
+    const  { createParser } = await import("eventsource-parser");
+    const { onMessage, timeout , ...fetchOptions } = options;
+    const controller = new AbortController();
+    const timeoutId = setTimeout(() => controller.abort(), timeout||30000)
+    
+    const res = await fetch2(url, {...fetchOptions,signal:controller.signal});
+    clearTimeout(timeoutId);
+    
+    if (!res.ok) {
+      let reason;
+      try {
+        reason = await res.text();
+      } catch (err) {
+        reason = res.statusText;
+      }
+      const msg = `ChatGPT error ${res.status}: ${reason}`;
+      const error = new ChatGPTError(msg, { cause: res });
+      error.statusCode = res.status;
+      error.statusText = res.statusText;
+      error.context = { url, options };
+      throw error;
+    }
+    const parser = createParser((event) => {
+      if (event.type === "event") {
+        onMessage(event.data);
+      }
+    });
+    if (!res.body.getReader) {
+      const body = res.body;
+      if (!body.on || !body.read) {
+        throw new ChatGPTError('unsupported "fetch" implementation');
+      }
+      body.on("readable", () => {
+        let chunk;
+        while (null !== (chunk = body.read())) {
+          parser.feed(chunk.toString());
+        }
+      });
+    } else {
+      for await (const chunk of streamAsyncIterable(res.body)) {
+        const str = new TextDecoder().decode(chunk);
+        parser.feed(str);
+      }
+    }
+}
+
+module.exports = fetchSSE;