Questions and answers

Here are some questions and answers to refresh your knowledge:

1. What is a ref?

   A React ref is a container to hold a persistent value. In general, you can use the value as a raw state with no update capability.

2. What is useRef?

   A useRef hook can be used to create a ref in a function component. Once created, it can be used as a persistent container during the life cycle of the component.

3. What are the common usages of useRef?

   One major usage of useRef is to hold a DOM instance that can be used to invoke native DOM functionalities. Another major usage of useRef is to sneak behind React to do something without kicking off the engine accidentally.