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)

   • seems really neat! I've seen it alot in my own research but haven't quite understood it's true purpose.

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

• To use React Router, we need to install react-router-dom through npm.

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 <BrowserRouter /> is a <Router> that uses the HTML5 history API to keep the UI in sync with the URL. The history API includes pushState, replaceState, and popState events. I found the forceRefresh attribute interesting and I am wondering if this lends to a bad UX.

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

• We would use <BrowserRouter /> in our app when we need to control navigation between two URLs. The way I see it used in the docs is that the basename can be used to set the suffix of the base URL to something new, and then a <Link /> can be used to determine where to go when the user intends to go further from that basename string. The getUserConfirmation function seems like something I have encountered before in my own user experience. Maybe it displays a message to the user that says 'Are you sure you want to go to this page?' Overall, <BrowserRouter /> seems useful for navigation and communicating with the user about their navigation choices.

Route Matchers

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

• The <Route /> component is responsible for rendering some UI when its path matches the current URL. This typically happens by rendering a component within the <Route />, which in turn is responsible for its returned/rendered JSX being displayed on the UI.

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

• The <Route /> component checks whether it should render something by matching the location of the application. For instance, if the exact path of the <Route /> is /login, the <Route /> component will render whatever it contains, such as a class or functional component which contains some returned JSX upon rendering. That component, suppose it is <Login />, will only be rendered when something like a <Link /> or <Redirect /> indicates a matching location for the one specified in the <Route />.

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

• The <Switch /> component renders the first child <Route> or <Redirect> that matches the location.

8. How does it decide what to render?

• The <Switch /> component decides what to render by finding the first matching path that matches the location. If there are multiple matches, it is better to use <Route> because <Route> will show the UI of every matching child component. <Switch /> reminds me, abstractly, of the .find() array prototype method in that it stops looking for matches past the first one.

Route Changers

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

• The <Link /> component provides declarative, accessible navigation around the application. In other words, it is activated when the user typically clicks on something (button, text, image, etc) and specifies where to go. My current understanding is that it is responsible for determining where the user is going next, and the <Route> from <App /> recognizes the link, and renders the React component accordingly.

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

• The <NavLink /> component is a version of <Link> that will add styling attributes (via activeStyle) to the rendered element when it matches the current URL. A user interacts with it by hovering and clicking on it to take them to a new view of the application.

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

• The <Redirect /> component will navigate to a new location when it is rendered. The new location overrides the current location in the history stack, similar to how a server responds with a 3XX status code from a client-side request. I believe it interferes with the user's history, which could cause bad UX when the user cannot successfully go back or forward with the browser-level navigation.