Separate flet extensions and add type hint

.gitignore

@@ -2,4 +2,5 @@
 playground/
 uploaded_files/
 assets/
-__pycache__/
+__pycache__/
+**/.DS_Store

app.py

@@ -5,6 +5,7 @@ from fastapi import FastAPI
 
 from flet_app import main
 from js_execution import mount_flet_app
+from flet_extensions import extend_flet_page
 
 # Set up basic logging configuration
 logging.basicConfig(level=logging.INFO, format='%(asctime)s - %(levelname)s - %(message)s')
@@ -18,5 +19,10 @@ async def lifespan(app: FastAPI):
 
 app = FastAPI(lifespan=lifespan)
 
+# Extend the Flet Page class
+extend_flet_page()
+
 # Use the new mount_flet_app function with the same arguments
-mount_flet_app(app, "/", flet_fastapi.app(main))
+flet_app = flet_fastapi.app(main)
+
+mount_flet_app(app, "/", flet_app)

flet.pyi

@@ -0,0 +1,28 @@
+from flet_core.page import Page as OriginalPage
+
+class Page(OriginalPage):
+    def eval_js(self, js_code: str) -> str:
+        """
+        Evaluates JavaScript code in the context of the current page.
+
+        This method allows execution of arbitrary JavaScript code within the
+        page's environment and returns the result as a string.
+
+        Args:
+            js_code (str): The JavaScript code to be executed.
+
+        Returns:
+            str: The result of the JavaScript execution as a string.
+
+        Raises:
+            Exception: If there's an error during JavaScript execution.
+
+        Example:
+            result = page.eval_js("return document.title;")
+        """
+        ...
+
+
+# Re-export other types from flet to maintain compatibility
+from flet import *
+from flet_runtime import *

flet_extensions.py

@@ -0,0 +1,11 @@
+import flet as ft
+from js_execution import js_execution_router
+
+def extend_flet_page():
+    async def eval_js(self: ft.Page, js_code: str) -> str:
+        endpoint, result_future = js_execution_router.create_dynamic_endpoint(js_code)
+        self.launch_url(endpoint, web_window_name="hidden-iframe")
+        return await result_future
+
+    if not hasattr(ft.Page, 'eval_js'):
+        ft.Page.eval_js = eval_js

js_execution.py

@@ -1,4 +1,3 @@
-import flet as ft
 import asyncio
 import logging
 from fastapi import FastAPI, Request
@@ -71,14 +70,6 @@ class JSExecutionRouter:
 
 js_execution_router = JSExecutionRouter()
 
-# Monkey patch the Page class to add eval_js method
-async def eval_js(self: ft.Page, js_code: str) -> str:
-    endpoint, result_future = js_execution_router.create_dynamic_endpoint(js_code)
-    self.launch_url(endpoint, web_window_name="hidden-iframe")
-    return await result_future
-
-ft.Page.eval_js = eval_js  # type: ignore
-
 def add_js_execution_routes(app: FastAPI):
     js_execution_router.init_app(app)