Debugging with DevTools

SDK Flavor Only

DevTools is only available in SDK flavor. It’s recommended to use SDK flavor to develop and test your app. And use other flavors for production.

Open Developer Tools

DevTools can be opened with keyboard shortcut F12 on Windows and Linux or ++i on Mac.

Alternatively, you may open DevTools programmatically using NW.js API win.showDevTools() for a window.

Node.js Modules Debugging

NW.js is running in Separate Context Mode by default. To debug Node.js modules, you can right click the app and choose “Inspect Background Page”. When stepping into Node.js modules in the debugger, the DevTools for background page is automatically focused and stopped at certain statement.

If your app is running under Mixed Context Mode, Node.js modules can be directly debugged within the same DevTools window of the window. See JavaScript Contexts in NW.js for the differences.

Remote Debugging

You can use the --remote-debugging-port=port command line option to specify which port the DevTools should listen to. For example, by running nw --remote-debugging-port=9222, you can open http://localhost:9222/ in your browser to visit the debugger remotely.

Using devtools extensions

Devtools extensions are fully supported, including the one for ReactJS, Vue.js, etc. To use it, add the permission “chrome-extension://*” to manifest.json of the devtools extension, and load it with --load-extension=path/to/extension when nw is started. The files for devtools extensions can be copied from extension folder of Chrome browser after you install them from Chrome Web Store.

React Example

Unpack them, download the SDK build and run it with: nw.exe --load-extension=path/to/devtools path/to/app/folder

The app is a simple react app with ‘package.json’ added. The devtools files are from the Chrome browser’s extension folder of official react devtools extension installed from Chrome Web store. Only the manifest file is modified to add the permission: “chrome-extension://*”.

Vue Example

  1. npm install --save-dev nw-vue-devtools-prebuilt
  2. Add this to your package.json:
    "chromium-args": "--load-extension='./node_modules/nw-vue-devtools-prebuilt/extension'",
  3. Vue.js must be in use in your app, and cannot be minified (use vue.js not vue.min.js).

This will automatically download the latest Vue-DevTools from the Chrome WebStore, unpack and modify it to work in NW.js.

If you are using nwjs-builder-phoenix then add in "chromium-args" to your package.json build.strippedProperties array.