Run/Debug configuration: React Native

Build and launch application

• Select the Build and launch checkbox if you are launching your application for the first time or if you have updated its native code since the last run.

• Clear this checkbox if you haven't made any changes to the native code of your application since the last build.

  When you start debugging, PyCharm waits for you to open your application in the simulator with the Remote debug enabled as described on the React Native official website

• If your application uses Expo, clear the checkbox because this bundler takes care of the process itself.

Platform

In this area, choose the platform for which the application is intended.

Depending on your choice, PyCharm will run the bundler with react-native run-ios or with react-native run-android.

• To emulate the Android platform, use an Android virtual device.

• To emulate the iOS platform, you need to install the ios-sim command-line tool globally. You can do it through the Node Package Manager (npm), see npm, pnpm, and Yarn, or by running the sudo npm install ios-sim -g command, depending on your operating system.

Learn more from the React Native official website.

Arguments

In this field, type the arguments to be passed to React Native, for example, specify the simulator type through the ‑‑simulator flag: ‑‑simulator="iPhone 4s".

Browser for debugging

In debugging React Native applications, PyCharm relies on the Chrome runtime, which is used by React Native itself. You can also use DevTools together with PyCharm. When you initiate a debugging session, PyCharm starts a new Chrome instance and attaches to it.

Bundler host

In this field, specify the host where the bundler runs, the default value is localhost.

If you are using Expo, you may need to change the default bundler host to ensure successful connection with the debugger. This connection may fail because PyCharm by default uses localhost to start debugging while Expo expects 127.0.0.1 or an external IP address depending on what is selected in Connection field of the Metro bundler configuration.

Bundler port

In this field, specify the port on which the bundler runs.

• PyCharm automatically chooses 8081, which is default for the React Native bundler. Learn more from the React Native official website.

• If your application uses Expo, you may need to change the port to 19000 or 19001, depending on the Expo configuration.

Node interpreter

In this field, specify the Node.js interpreter to use. This can be a local Node.js interpreter or a Node.js on Windows Subsystem for Linux.

React Native package

In this field, specify the path to react-native-cli.

Working directory

specify the working directory of the application. By default, the field shows the project root folder.

Environment variables

In this field, optionally, type the environment variables for executing the react-native run-android or the react-native run-ios command.

Name

Specify a name for the run/debug configuration to quickly identify it when editing or running the configuration, for example, from the Run popup Alt+Shift+F10.

Allow parallel run

Select to allow running multiple instances of this run configuration in parallel.

By default, it is disabled, and when you start this configuration while another instance is still running, PyCharm suggests to stop the running instance and start another one. This is helpful when a run/debug configuration consumes a lot of resources and there is no good reason to run multiple instances.

Store as project file

Save the file with the run configuration settings to share it with other team members. The default location is .idea/runConfigurations. However, if you do not want to share the .idea directory, you can save the configuration to any other directory within the project.

By default, it is disabled, and PyCharm stores run configuration settings in .idea/workspace.xml.

Alt+Insert

Create a run/debug configuration.

Alt+Delete

Delete the selected run/debug configuration. Note that you cannot delete default configurations.

Ctrl+D

Create a copy of the selected run/debug configuration. Note that you create copies of default configurations.

The button is displayed only when you select a temporary configuration. Click this button to save a temporary configuration as permanent.

Move into new folder / Create new folder. You can group run/debug configurations by placing them into folders.

To create a folder, select the configurations within a category, click , and specify the folder name. If only a category is in focus, an empty folder is created.

Then, to move a configuration into a folder, between the folders or out of a folder, use drag or and buttons.

To remove grouping, select a folder and click .

Click this button to sort configurations in the alphabetical order.

Alt+Insert

Click this icon to add one of the following available tasks:

• Run External tool: select to run an external application. In the dialog that opens, select one or multiple applications you want to run. If it is not defined in PyCharm yet, add its definition. For more information, see External tools and External Tools.

• Run Another Configuration: select to execute another run/debug configuration. In the dialog that opens, select the configuration to be run.

• Launch Web Browser: select this option to have a browser started. In the dialog that opens, select the type of the browser and provide the start URL. Also, specify if you want the browser be launched with JavaScript debugger.

• Run File Watchers: select this option to have PyCharm apply all the currently active File Watchers.

• Run Grunt task: select this option to run a Grunt task.

  In the Grunt task dialog that opens, specify the Gruntfile.js where the required task is defined, select the task to execute, and specify the arguments to pass to the Grunt tool.

  Specify the location of the Node.js interpreter, the parameters to pass to it, and the path to the grunt-cli package.

• Run gulp task: select this option to run a Gulp task.

  In the Gulp task dialog that opens, specify the Gulpfile.js where the required task is defined, select the task to execute, and specify the arguments to pass to the Gulp tool.

  Specify the location of the Node.js interpreter, the parameters to pass to it, and the path to the gulp package.

• Run npm script: select this option to execute an npm script.

  In the NPM Script dialog that opens, specify the npm run/debug configuration settings.

• Start React Native Bundler: select this option to run the bundler automatically, as part of a running or debugging session. by default, this is done through react-native start. If your application uses Expo, you need to run the development server via the start npm task. To do that, click , then in the Configure React Native dialog, choose npm script and select start from the list.

• Compile TypeScript: select to run the built-in TypeScript compiler and thus make sure that all the changes you made to your TypeScript code are reflected in the generated JavaScript files. In the TypeScript Compile Settings dialog that opens, select or clear the Check errors checkbox to configure the behaviour of the compiler in case any errors are detected:

  • If the Check errors checkbox is selected, the compiler will show all the errors and the run configuration will not start.

  • If the Check errors checkbox is cleared, the compiler will show all the detected errors but the run configuration still will be launched.

• Generate CoffeeScript Source Maps: select this option to generate the source maps for your CoffeeScript sources. In the dialog that opens, specify where your CoffeeScript source files are located.

• Run Remote External Tool: adds a remote SSH external tool.

Alt+Delete

Click this icon to remove the selected task from the list.

Enter

Click this icon to edit the selected task. Make the necessary changes in the dialog that opens.

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Alt+Up/Alt+Down

Click these icons to move the selected task one line up or down in the list. The tasks are performed in the order that they appear in the list.

Show this page

Select this checkbox to show the run/debug configuration settings prior to actually starting the run/debug configuration.

Activate tool window

By default this checkbox is selected and the Run or the Debug tool window opens when you start the run/debug configuration.

Otherwise, if the checkbox is cleared, the tool window is hidden. However, when the configuration is running, you can open the corresponding tool window for it yourself by pressing Alt+4 or Alt+5.