feat: prose completion api

web/src/core/api/chat.ts

@@ -9,7 +9,7 @@ import { sleep } from "../utils";
 import { resolveServiceURL } from "./resolve-service-url";
 import type { ChatEvent } from "./types";
 
-export function chatStream(
+export async function* chatStream(
   userMessage: string,
   params: {
     thread_id: string;
@@ -32,13 +32,19 @@ export function chatStream(
   if (location.search.includes("mock") || location.search.includes("replay=")) {
     return chatReplayStream(userMessage, params, options);
   }
-  return fetchStream<ChatEvent>(resolveServiceURL("chat/stream"), {
+  const stream = fetchStream(resolveServiceURL("chat/stream"), {
     body: JSON.stringify({
       messages: [{ role: "user", content: userMessage }],
       ...params,
     }),
     signal: options.abortSignal,
   });
+  for await (const event of stream) {
+    yield {
+      type: event.event,
+      data: JSON.parse(event.data),
+    } as ChatEvent;
+  }
 }
 
 async function* chatReplayStream(

web/src/core/sse/StreamEvent.ts

@@ -2,6 +2,6 @@
 // SPDX-License-Identifier: MIT
 
 export interface StreamEvent {
-  type: string;
-  data: object;
+  event: string;
+  data: string;
 }

web/src/core/sse/fetch-stream.ts

@@ -3,10 +3,10 @@
 
 import { type StreamEvent } from "./StreamEvent";
 
-export async function* fetchStream<T extends StreamEvent>(
+export async function* fetchStream(
   url: string,
   init: RequestInit,
-): AsyncIterable<T> {
+): AsyncIterable<StreamEvent> {
   const response = await fetch(url, {
     method: "POST",
     headers: {
@@ -39,7 +39,7 @@ export async function* fetchStream<T extends StreamEvent>(
       }
       const chunk = buffer.slice(0, index);
       buffer = buffer.slice(index + 2);
-      const event = parseEvent<T>(chunk);
+      const event = parseEvent(chunk);
       if (event) {
         yield event;
       }
@@ -47,9 +47,9 @@ export async function* fetchStream<T extends StreamEvent>(
   }
 }
 
-function parseEvent<T extends StreamEvent>(chunk: string) {
-  let resultType = "message";
-  let resultData: object | null = null;
+function parseEvent(chunk: string) {
+  let resultEvent = "message";
+  let resultData: string | null = null;
   for (const line of chunk.split("\n")) {
     const pos = line.indexOf(": ");
     if (pos === -1) {
@@ -58,16 +58,16 @@ function parseEvent<T extends StreamEvent>(chunk: string) {
     const key = line.slice(0, pos);
     const value = line.slice(pos + 2);
     if (key === "event") {
-      resultType = value;
+      resultEvent = value;
     } else if (key === "data") {
-      resultData = JSON.parse(value);
+      resultData = value;
     }
   }
-  if (resultType === "message" && resultData === null) {
+  if (resultEvent === "message" && resultData === null) {
     return undefined;
   }
   return {
-    type: resultType,
+    event: resultEvent,
     data: resultData,
-  } as T;
+  } as StreamEvent;
 }