---
# System prepended metadata

title: 11/17大二部課
tags: [112-1]

---

# Todo
## Web
[CourseMap](https://hackmd.io/zpak6bIvQtaHMJjTVjgAsg)
- [ ] 進度
## Server
- [ ] email server
- [ ] remote attach security
- [ ] FireWall
- [ ] VPN?

# Performance
- Lazy Load
    - [img](https://www.freecodecamp.org/news/how-to-lazy-load-images-in-react/)
![image](https://hackmd.io/_uploads/S1jtKTNVa.png)

    - [code](https://react.dev/reference/react/lazy#load)

- [memo](https://react.dev/reference/react/memo)
    - memo
    - useCallback
    - useMemo
### When to use?
* Use React Memo if your component will render quite often.
* Use it when your component often renders with the same props.
* Use it in pure functional components alone.
* Use it if your component is big enough (contains a decent amount of UI elements or complex logic) to have props equality check.



ref:
- [React 性能優化那件大事，使用 memo、useCallback、useMemo](https://medium.com/%E6%89%8B%E5%AF%AB%E7%AD%86%E8%A8%98/react-optimize-performance-using-memo-usecallback-usememo-a76b6b272df3)
- [What is React memo and how to use it?](https://hygraph.com/blog/react-memo)