> For the complete documentation index, see [llms.txt](https://koseungbin.gitbook.io/wiki/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://koseungbin.gitbook.io/wiki/books/undefined/part-3./observer.md).

# 옵저버(Observer) 패턴