NativeScript Extension for Visual Studio Code

Installation

To install the NativeScript extension for Visual Studio Code open the Command Palette (F1 or Cmd+Shift+P) and run Extensions: Install Extension command, then search for 'NativeScript' and choose it from the list.

After the installation completes, the extension appears in the list of installed extensions. You can see it if you run Extensions: Show Installed Extensions command from the Command Palette.

Debugging

Open your application root folder, created with tns create command, in Visual Studio Code.

Generate launch configurations

Click the debugging icon in the View bar, and then click the gear icon to choose the NativeScript debug environment. A launch.json file should be generated in your .vscode folder, containing 4 default launch configurations - Launch on iOS, Attach on iOS, Launch on Android and Attach on Android. You can always add your own debug configuration or alter the existing ones just by editing the launch.json file.

Launch an application with the debugger

Choose one of the launch configurations (e.g., Launch on iOS) and press the Start Debugging button next to the menu. This will trigger a NativeScript CLI command which will build, deploy and run your app in an iOS device or emulator and attach the Visual Studio Code debugger. If you want the execution to stop on the first JavaScript/TypeScript statement, functionality set the stopOnEntry flag to true in your launch.json configuration.

Once the debugger is attached you can inspect scope variables, set breakpoints, watch expressions, execute code while the app is paused on a breakpoint etc. You can find more information about the debugging support in Visual Studio Code in the VS Code Debugging Guide.

What's more awesome is that the default launch configurations take advantage of the NativeScript CLI functionality. Therefore, while the VS Code debugger is attached, every change to the app's source will trigger a livesync (after saving the altered file) which will update and restart the target application while the VS Code debugger is automatically reattached to the new app instance preserving all breakpoints and watched expressions. The watching feature can be disabled by setting the watch flag to false in your launch.json configurations.

Attach the debugger to an already running app

If you have an already running NativeScript application in your emulator or device, you can attach the VS Code debugger to it, without even restarting the app. Just select the desired attach configuration through the debug configuration menu and press the start button.

Supply additional arguments to the debug command

Under the hood, starting a particular debug configuration executes the tns debug command with various arguments. You can append additional arguments by supplying them in the tnsArgs property of a debug configuration definition in launch.json. For example, if you add "tnsArgs": "--log=trace" in the Launch on iOS configuration, in the background VS Code will execute the tns debug ios --no-client --log=trace command, which will give you more verbose information in the Debug Console.

Turn on diagnostic logging

If the diagnosticLogging flag for a particular debug configuration in launch.json file is set to true (its default value is false), diagnostic messages will be logged on the debugger console after attaching the debugger to the NativeScript application. This is useful for rough debugging of the extension itself because all sent/received messages that are part of the communication between the frontend and the backend are logged.

Use NativeScript-specific commands

Type nativescript in the Command Palette, and you will see all NativeScript-specific commands. Currently, there are only two of the, but the list will grow in the future.

The Run on Android/iOS command is the equivalent of tns run in the NativeScript CLI. It lets you build, deploy and run your app on an emulator/device directly from Visual Studio Code.

NativeScript CLI version detection

The extension depends on a globally installed NativeScript CLI. It will show an error message if it can't find it.

The extension requires a specific NativeScript CLI version and if you have another version installed, you will see a warning message. The extension is likely to work with the unsupported version, but it is recommended to update the NativeScript CLI or the VS Code extension.