VS Code Launch Settings

Debugging in the Editor

(content from the Create React App documentation)

This feature is currently only supported by Visual Studio Code and WebStorm.

Visual Studio Code and WebStorm support debugging out of the box with Create React App. This enables you as a developer to write and debug your React code without leaving the editor, and most importantly it enables you to have a continuous development workflow, where context switching is minimal, as you don’t have to switch between tools.

Visual Studio Code

You would need to have the latest version of VS Code and VS Code Chrome Debugger Extension installed.

Then add the block below to your launch.json file and put it inside the .vscode folder in your app’s root directory.

{
  "version": "0.2.0",
  "configurations": [{
    "name": "Chrome",
    "type": "chrome",
    "request": "launch",
    "url": "http://localhost:3002",
    "webRoot": "${workspaceRoot}/src",
    "sourceMapPathOverrides": {
      "webpack:///src/*": "${webRoot}/*"
    }
  }]
}

Note: the URL may be different if you've made adjustments via the HOST or PORT environment variables.

Start your app by running npm start, and start debugging in VS Code by pressing F5 or by clicking the green debug icon. You can now write code, set breakpoints, make changes to the code, and debug your newly modified code—all from your editor.

Having problems with VS Code Debugging? Please see their troubleshooting guide.

Debugging Tests

There are various ways to setup a debugger for your Jest tests. We cover debugging in Chrome and Visual Studio Code.

Note: debugging tests requires Node 8 or higher.

Debugging Tests in Chrome

Add the following to the scripts section in your project's package.json

"scripts": {
    "test:debug": "react-scripts --inspect-brk test --runInBand --env=jsdom"
  }

Place debugger; statements in any test and run:

$ npm run test:debug

This will start running your Jest tests, but pause before executing to allow a debugger to attach to the process.

Open the following in Chrome

about:inspect

After opening that link, the Chrome Developer Tools will be displayed. Select inspect on your process and a breakpoint will be set at the first line of the react script (this is done simply to give you time to open the developer tools and to prevent Jest from executing before you have time to do so). Click the button that looks like a "play" button in the upper right hand side of the screen to continue execution. When Jest executes the test that contains the debugger statement, execution will pause and you can examine the current scope and call stack.

Note: the --runInBand cli option makes sure Jest runs test in the same process rather than spawning processes for individual tests. Normally Jest parallelizes test runs across processes but it is hard to debug many processes at the same time.

Debugging Tests in Visual Studio Code

Debugging Jest tests is supported out of the box for Visual Studio Code.

Use the following launch.json configuration file:

{
  "version": "0.2.0",
  "configurations": [
    {
      "name": "Debug CRA Tests",
      "type": "node",
      "request": "launch",
      "runtimeExecutable": "${workspaceRoot}/node_modules/.bin/react-scripts",      
      "args": [
        "test",
        "--runInBand",
        "--no-cache",
        "--env=jsdom"
      ],
      "cwd": "${workspaceRoot}",
      "protocol": "inspector",
      "console": "integratedTerminal",
      "internalConsoleOptions": "neverOpen"
    }
  ]
}