2006 React-Router-Prework.md

React Router Prework

This gist contains a short assignment I'd like everyone to complete before our formal lesson. The prework involves reading some of the React Router documentation, and will allow us to keep the lesson more hands on.

Instructions

1. Fork this gist
2. On your own copy, go through the listed readings and answer associated questions
3. Comment a link to your forked copy on the original gist

Questions / Readings

Router Overview

React Router is a library that allows us to make our single page React applications mimic the behavior of multipage apps. It provides the ability to use browser history, allowing users to navigate with forward / back buttons and bookmark links to specific views of the app. Most modern sites use some form of routing. React Router exposes this functionality through a series of components. Let's start by looking at the overall structure of an app using router:

1. Take a look at the quick start page of the React Router docs. Take note of the syntax and organization of the page. No worries if this looks unclear right now! (nothing to answer here)

2. What package do we need to install to use React Router?

npm install react-router-dom

Router Components

React Router provides a series of helpful components that allow our apps to use routing. These can be split into roughly 3 categories:

• Routers
• Route Matcher
• Route Changers

Routers

Any code that uses a React-Router-provided component must be wrapped in a router component. There are lots of router components we can use, but we'll focus on one in particular. Let's look into the docs to learn more.

3. What is a <BrowserRouter />?

• a router component that allows us to take advantage of the React Router. Should be rendered at root and wrapping our top level component element, usually <App />

4. Why would we use <BrowserRouter /> in our apps?

• so we can navigate more traditionally in the web experience. Allows access to the other components (Route, Switch, Link, etc.). Forward and backward browser buttons work as expected. With the right setup, you could send someone a url path to a deeper part of your site. With proper setup, can refresh the page and maintain all details.

Route Matchers

5. What does the <Route /> component do?

• Will allow you to declare a path for where the enclosed component should render. ex - only show <MovieDetails /> when at the path /movies/:moview_id. <Route path="/movies/:movie_id" render={<MovieDetails />}/>

6. How does the <Route /> component check whether it should render something?

• It will check whether the URL matches the path prop

7. What does the <Switch /> component do?

• It will render ONLY one <Route /> component nested insdide of itself. It will find the Route component whose path matches the current URL and render only that component. Route components should generally live inside of a Switch component and go from most to least specific routes.

8. How does it decide what to render?

• It will find the Route component whose path matches the current URL and render only that component. However, unless using the exact keyword, the Switch component is inclusive in its search - if the URL is http://.../movies, and a componenet with a path .../ is nested higher in Switch than a component with the path .../movies, Switch will render the first component because the slash / matched the / inside of the url http://.../movies. A path of / will always match - it should be placed lowest in the nesting order.

Route Changers

9. What does the <Link /> component do? How does a user interact with it?

• Allows you to create a clickable link (wrap the item you'd like to link in the component tag). User will click the linked item and that will change the current URL path to whatever is inside of the Link in the to= prop.

10. What does the <NavLink /> component do? How does a user interact with it?

• I've read that the greatest difference is some built in style, where the link styles itself as active if the to prop matches the current URL path.

11. What does the <Redirect /> component do?

• Allows one to force navigation to a given path without requiring a user action. Example, if you land on an error page because of some error, you may be automatically redirected to the /home page after some moments.