React Unidirectional Data Lab


  1. Coordinate components, actions, and stores to create a unidirectional data flow
  2. Practice modularizing React applications


In this lab we're going to practice modularizing component architectures by building a note taking application.

This is what it's going to look like:



Screenshot Components

Our application consists of a couple of components that we're going to implement as part of this lab. As usual, the tests will guide us while building them out.

<App />

The primary container of our application is the <App /> component. <App /> adds a listener to the fileStore store when being mounted.

The <App /> component has two child components: <Sidebar /> and <FileView />.

<Sidebar />

<Sidebar /> contains a list of all available notes.

It doesn't subscribe to the store directly, but instead receives the files prop from the <App /> component. <Sidebar /> is stateless. It renders a list of <SidebarItem /> components.

<SidebarItem />

A <SidebarItem /> represents a single note entry in the sidebar. If the note is currently selected, it should have a light background (don't worry about the styling, the CSS is taken care of).

<FileView />

On the right hand side of the app, we can see the so-called "FileView". The <FileView /> component renders a single file.

Our users can edit the file by entering text into the <textarea />.

<Toolbar />

On the top, we can see a toolbar. The <Toolbar /> component contains two buttons. When a user click on the "Add note" button, a new file is added to the end of the fileStore. When a user clicks the "Remove note" button, the currently selected file should be deleted from the fileStore.

There should always be at least one file in the sidebar. If the user attempts to delete the last remaining note, we simply clear the file instead of deleting the note.


Our editor uses a single fileStore singleton. fileStore inherits from Store, which implements a generic store.


Unlock your future in tech
Learn to code.

Learn about Flatiron School's Mission

With a new take on education that falls somewhere between self-taught prodigy and four-year computer science degree, the Flatiron School promises to turn students with little programming experience into developers.

In the six months since the Manhattan coding school was acquired by WeWork, it has spawned locations in Washington, D.C., Brooklyn, and London. Now, WeWork is opening a fourth Flatiron School location, this time in Houston.

Adam Enbar, Flatiron School's cofounder, believes now is the time to grow. "How the world is changing has impacted working and learning in very similar ways. We think education fundamentally is about one thing: enabling people to pursue a better life."

Learn. Love. Code.
Students come to Flatiron School to change their lives. Join our driven community of career-changers and master the skills you need to become a software engineer or a data scientist.
Find Us