Debug Jest Unit Tests with VS Code breakpoints in React Native

Cristian Gutu
By Cristian Gutu ·

An excellent way to debug your Jest unit tests is by adding breakpoints in the .test.ts file and also in the .ts one.

Visual Studio Code can support this by adding a new item in the configurations list from the launch.json file. This config will also read your jest.config.js file.

Make sure you add the following config:

  // put this inside /.vscode dir
  // Use IntelliSense to learn about possible attributes.
  // Hover to view descriptions of existing attributes.
  // For more information, visit:
  "version": "0.2.0",
  "configurations": [
      "type": "node",
      "request": "launch",
      "name": "Jest: current file",
      //"env": { "NODE_ENV": "test" },
      "program": "${workspaceFolder}/node_modules/.bin/jest",
      "args": ["${fileBasenameNoExtension}", "--config", "jest.config.js"],
      "console": "integratedTerminal",
      "disableOptimisticBPs": true,
      "windows": {
        "program": "${workspaceFolder}/node_modules/jest/bin/jest"

This config will run all the unit tests from the currently opened .test.ts file. Add your breakpoints and turn on the debugger.

Here is a short demo:

jest breakpoint debug

Another handy way to trigger those breakpoints is to have the vscode-jest plugin installed.

This plugin has a lot of features:

  • Starts Jest automatically for most projects with runnable jest configurations.
  • Fully integrated with the VS Code TestExplorer.
  • Supports both automatic and manual test runs at any level, and easy-switch via UI.
  • Supports additional IntelliSense for jest methods.
  • Show fails inline of the expect function, as well as in the problem inspector.
  • View and update snapshots interactively.
  • Help debug jest tests in VS Code.
  • Show coverage information in files being tested.
  • Supports monorepo, react, react-native, vue and various configurations/platforms.

With this plugin, you can also debug individual tests, take a look here:

jest breakpoint debug

I hope this will help you when trying to figure out why some tests are not passing or why some mocks are not properly configured.