fix: avoid unintended metadata parsing (#44)

package.json

@@ -1,7 +1,7 @@
 {
   "name": "@magicul/react-chat-stream",
   "description": "A React hook that lets you easily integrate your custom ChatGPT-like chat in React.",
-  "version": "0.5.0",
+  "version": "0.5.1",
   "main": "dist/index.js",
   "types": "dist/index.d.ts",
   "homepage": "https://github.com/XD2Sketch/react-chat-stream#readme",

src/hooks/useChatStream.ts

@@ -1,6 +1,7 @@
 import { ChangeEvent, FormEvent, useState } from 'react';
 import { decodeStreamToJson, getStream } from '../utils/streams';
 import { UseChatStreamChatMessage, UseChatStreamInput } from '../types';
+import { extractJsonFromEnd } from '../utils/json';
 
 const BOT_ERROR_MESSAGE = 'Something went wrong fetching AI response.';
 
@@ -41,7 +42,6 @@ const useChatStream = (input: UseChatStreamInput) => {
     const stream = await getStream(message, input.options, input.method);
     const initialMessage = addMessage({ content: '', role: 'bot' });
     let response = '';
-    let metadata = {};
 
     for await (const chunk of decodeStreamToJson(stream)) {
       if (!charactersPerSecond) {
@@ -51,10 +51,10 @@ const useChatStream = (input: UseChatStreamInput) => {
       }
 
       if (input.options.useMetadata) {
-        try {
-          metadata = JSON.parse(chunk.trim());
+        const metadata = extractJsonFromEnd(chunk);
+        if (metadata) {
           return { ...initialMessage, content: response, metadata: metadata };
-        } catch {}
+        }
       }
 
       // Stream characters one by one based on the characters per second that is set.

src/utils/json.ts

@@ -0,0 +1,20 @@
+export const extractJsonFromEnd = (chunk: string) => {
+  const chunkTrimmed = chunk.trim();
+
+  const jsonObjectRegex = /({[^]*})\s*$/;
+  const match = chunkTrimmed.match(jsonObjectRegex);
+
+  if (!match) {
+    return null;
+  }
+
+  const jsonStr = match[1];
+  try {
+    const parsedData = JSON.parse(jsonStr);
+    if (typeof parsedData === 'object' && parsedData !== null && !Array.isArray(parsedData)) {
+      return parsedData;
+    }
+  } catch {}
+
+  return null;
+};