Putting it all together

Thinking in React

1. How would you break a mock into a component heirarchy?

The first thing you'll want to do is to draw boxes around every component
Identified the components in our mock,
Rerange them into a hierarchy

Components that appear within another component in the mock should appear as a child in the hierarchy

2. What is the `single responsibility` principle and how does it apply to components?

Th Component should ideally only do one thing. If it ends up growing, it should be decomposed into smaller subcomponents.

3. What does it mean to build a `static` version of your application?

To build a static version of your app that renders your data model, you'll want to build components that reuse other components and pass data using props

4. Once you have a `static` application, what do you need to add?

Props are a way of passing data from parent to child. If you are familiar with the concept of state, don't use state at all to build this static version.
State is reserved only for interactivity, that is, data that changes over time. Since this is a static version of the app, you don't need it.

5. What are the three questions you can ask to determine if something is state?

Is it passed in from a parent via props? If so, it probably isn't state.
Does it remain unchanged over time? If so, it probably isn't state.
Can you compute it based on any other state or props in your component? If so, it isn't state.

6. How can you identify where state needs to live?

Identify every component that renders something based on that state.
Find a common owner component.
Either the common owner or another component higher up in the hierarchy should own the state.
If you can't find a component where it makes sense to own the state, create a new component solely for holding the state and add it somewhere in the hierarchy above the common owner component.