Project Cleanup

Clean out some unneeded code from the default app, tweak some configuration in the IDE, and tour a few more features.

In our previous step we generated a project then took a look around. We'll use that step as the starting point and do some cleaning up:

  • Use the IDE to reformat code

  • Strip out unneeded "Hello World" artifacts to simplify our starting point

Along the way we'll show some IDE features in action.


The finished code for this tutorial step is in the repository.

Reformatting Code

We currently have the test runner script running. If you have it running via npm run-script test in a terminal window, terminate that process with Ctrl-C or the equivalent. If you ran it in PyCharm Professional, close that tool window (and click Terminate on the dialog.)

In PyCharm Professional, reformatting code is simple. In fact, it's something you will do constantly. You currently have App.test.tsx open. Let's use the Reformat Code action (Ctrl-Alt-L Win/Linux, Alt-Cmd-L macOS) to set everything to proper indentation.

Close that tab and go back to App.tsx. Do the same Reformat Code operation there as well.


This is a...complicated topic.

In the world of React, ESLint has become very popular and create-react-app comes with ESLint preconfigured. TSLint is popular for TypeScript projects, but create-react-app --typescript doesn't use it. Why? The TypeScript and TSLint teams are joining forces to enhance ESLint's TypeScript support.

Prettier is another linting project that has gotten popular. WebStorm has direct integration for can detect its presence, turn it on, and provide a shortcut for a Reformat with Prettier action. For this tutorial, since CRA doesn't support Prettier, we'll skip it.

Thus, for this tutorial, we will stick with the IDE's built-in code reformatter and rules.

Clean Up, Clean Up

In App.tsx, let's do some steps to make a simpler starting point for the rest of the series. First, remove all the markup in the render method and replace it:

render() {
return (
<h1>Hello React</h1>

In PyCharm Professional you can quickly generate markup using Emmet. Highlight the existing div to replace and enter div>h1<enter>Hello React:

Use Emmet to generate HTML markup

We have an ESLint error on line 2, which we can see by hovering over the gray squiggly line:

Unused import logo from './logo.svg

We could stop what we're doing, move that line, and delete it. But the IDE makes this easy with the Optimize Imports action (Ctrl-Alt-O for Win/Linux and macOS). Invoke that and remove the unused import.

While you're at it:

  • Delete the import './App.css'; line

  • Delete the logo.svg and App.css files

In PyCharm, when you do a delete, you're actually doing a "Safe Delete", with the option to look for places in the project where you might have used it. Give it a try by starting the delete process on index.css. The IDE will warn you:

Safe Delete looks for usages and warns

More IDE Goodies

We're talking about cleanup. Let's look at some other ways the IDE can do our janitorial work.

Let's say were in a file and were writing something like class App and hadn't imported React yet.

Simulate this by changing the first line to the following:

import { Component } from react;

The IDE tells you about the error, with a red squiggly on the usage of React.

Get warnings on missing imports

Click on it, then Alt-Enter and choose Add Import Statement. PyCharm generates the proper import:

Let the IDE generate missing imports

Let's say I wanted to rename App. Where is it being used? Right-click on it, then choose Find Usages. A window pops up. Turns out it's being used in a lot of places. Double-click on the usage in index.tsx. PyCharm opens the file, moves to the line, and puts the cursor in the right spot.

How about the other're sitting on the usage and want to go to the definition? Use Cmd-B to jump to the class that defines App.

We could now start the process of renaming by visiting all the usages. Bleh. Can't we let the IDE do it for me? Click on App in class App and hit Ctrl-T, then choose Rename to Refactor Rename the class to MyApp:

Let the IDE rename symbols in all usages

In the tool window showing you the consequences, choose Do Refactor.

Oh no, that's not what I wanted! Do I have to do another refactor? Nope. The IDE did all those operations in one editor transaction. Just use Undo and say Ok on the dialog.