`useState()` Hook

Readings

What was the motivation for introducing Hooks?
- Hooks solve a wide variety of seemingly unconnected problems in React that we’ve encountered over five years of writing and maintaining tens of thousands of components. Whether you’re learning React, use it daily, or even prefer a different library with a similar component model, you might recognize some of these problems
What changes are important regarding implementing Hooks versus Component Classes?
- With Hooks, you can extract stateful logic from a component so it can be tested independently and reused
Hooks allow you to reuse stateful logic without changing ____.
- component hierarchy

Name two rules imposed by React Hook usage.
- only call hooks at top level and only call hooks from react functions
How would you identify a custom Hook and why might you create one?
- the word use identifies a custom hook and so you can call other hooks

What is a Hook?
- They let you use state and other React features without writing a class
When would I use the useState Hook?
- If you write a function component and realize you need to add some state to it, previously you had to convert it to a class. Now you can use a Hook inside the existing function component
If you were to add React state to a function component by declaring a state variable:
- What does calling useState do?
  - It declares a “state variable”. Our variable is called count but we could call it anything else, like banana. This is a way to “preserve” some values between the function calls
- What do we pass to useState as an argument?
  - The only argument to the useState() Hook is the initial state. Unlike with classes, the state doesn’t have to be an object. We can keep a number or a string if that’s all we need
- What does useState return?
  - It returns a pair of values: the current state and a function that updates it

I want to be proficient in react, so learning and watching how hooks are used is what I’m look forward to.