gradio: Custom Components Guide does not seem to lead to a working example

Describe the bug

I tried following the guide at https://www.gradio.app/guides/custom-components-in-five-minutes.

I didn’t make any code-changes yet, so I’m expecting to see my new component as a SimpleTextbox.

However when I go to the frontend URL I only see a screen with an infinite “Loading” text. The console shows these errors:

Uncaught SyntaxError: Unexpected token '{' (at (index):55:35)

svelte.js:3232 Uncaught (in promise) TypeError: Cannot read properties of undefined (reading '$$')
    at init (svelte.js:3232:44)
    at new Blocks (Blocks.svelte:669:31)
    at Array.create_if_block_1 (index.svelte:184:43)
    at Object.p (Index.svelte:394:41)
    at update_slot_base (svelte.js:203:8)
    at Object.p (core.js:231:1)
    at update (svelte.js:2128:30)
    at flush (svelte.js:2088:5)

Line 55 at index looks like this:

<script>window.gradio_config = {{ config | toorjson }};</script>

Is this a bug? Am I missing a step?

Have you searched existing issues? 🔎

• I have searched and found no existing issues

Reproduction

Follow the guide until you enter the frontend URL.

Screenshot

No response

Logs

No response

System Info

Gradio Environment Information:
------------------------------
Operating System: Windows
gradio version: 4.10.0
gradio_client version: 0.7.3

------------------------------------------------
gradio dependencies in your environment:

aiofiles: 23.2.1
altair: 5.2.0
fastapi: 0.105.0
ffmpy: 0.3.1
gradio-client==0.7.3 is not installed.
httpx: 0.24.1
huggingface-hub: 0.19.4
importlib-resources: 6.1.1
jinja2: 3.1.2
markupsafe: 2.1.3
matplotlib: 3.8.2
numpy: 1.23.5
orjson: 3.9.10
packaging: 23.2
pandas: 2.1.4
pillow: 9.5.0
pydantic: 2.5.2
pydub: 0.25.1
python-multipart: 0.0.6
pyyaml: 6.0.1
semantic-version: 2.10.0
tomlkit==0.12.0 is not installed.
typer: 0.9.0
typing-extensions: 4.8.0
uvicorn: 0.24.0.post1
authlib; extra == 'oauth' is not installed.
itsdangerous; extra == 'oauth' is not installed.


gradio_client dependencies in your environment:

fsspec: 2023.12.1
httpx: 0.24.1
huggingface-hub: 0.19.4
packaging: 23.2
typing-extensions: 4.8.0
websockets: 11.0.3

Severity

Blocking usage of gradio