IntelliJ IDEA 14.0.0 Web Help

Transpiling TypeScript to JavaScript

TypeScript code is not processed by browsers that work with JavaScript code. Therefore to be executed, TypeScript code has to be translated into JavaScript. This operation is referred to as transpilation and the tools that perform it are called transpilers.

IntelliJ IDEA supports integration with the typescript tool. The TypeScript transpiler translates TypeScript code into JavaScript and creates source maps that set correspondence between lines in your TypeScript code and in the generated JavaScript code, otherwise your breakpoints will not be recognised and processed correctly.

In IntelliJ IDEA, transpiler configurations are called File Watchers. For each supported transpiler, IntelliJ IDEA provides a predefined File Watcher template. Predefined File Watcher templates are available at the IntelliJ IDEA level. To run a transpiler against your project files, you need to create a project-specific File Watcher based on the relevant template, at least, specify the path to the transpiler to use on your machine.

On this page:

Prerequisites

  1. Download and install Node.js. The framework is required for two reasons:
    • The TypeScript transpiler is started through Node.js.
    • NPM, which is a part of the framework, is also the easiest way to download the TypeScript transpiler.

  2. If you are going to use the command line mode, make sure the following paths are added to the PATH variable:
    1. The path to the parent folder of the Node.js executable file.
    2. The path to the npm folder.

    This enables you to launch the TypeScript transpiler and npm from any folder.

  3. Install and enable the NodeJS repository plugin.

    The plugin is not bundled with IntelliJ IDEA, but it is available from the JetBrains plugin repository. Once enabled, the plugin is available at the IDE level, that is, you can use it in all your IntelliJ IDEA projects. See Installing, Updating and Uninstalling Repository Plugins and Enabling and Disabling Plugins for details.

  4. Install and enable the File Watchers repository plugin.

    The plugin is not bundled with IntelliJ IDEA, but it is available from the IntelliJ IDEA plugin repository. Once enabled, the plugin is available at the IDE level, that is, you can use it in all your IntelliJ IDEA projects. See Installing, Updating and Uninstalling Repository Plugins and Enabling and Disabling Plugins for details.

Installing the TypeScript transpiler

The easiest way to install the TypeScript transpiler is to use the Node Package Manager (npm), which is a part of Node.js.

Depending on the desired location of the TypeScript transpiler executable file, choose one of the following methods:

  • Install the transpiler globally at the IntelliJ IDEA level so it can be used in any IntelliJ IDEA project.
  • Install the transpiler in a specific project and thus restrict its use to this project.
  • Install the transpiler in a project as a development dependency.

In either installation mode, make sure that the parent folder of the TypeScript transpiler is added to the PATH variable. This enables you to launch the transpiler from any folder.

IntelliJ IDEA provides user interface both for global and project installation as well as supports installation through the command line.

Installing the TypeScript transpiler globally

  • Run the installation from the command line in the global mode:
    1. Launch the embedded Terminal by hovering your mouse pointer over show_tool_window_bars in the lower left corner of IntelliJ IDEA and choosing Terminal from the menu (see Working with Embedded Local Terminal for details).
    2. Switch to the directory where NPM is stored or define a PATH variable for it so it is available from any folder, see Installing NodeJs.
    3. Type the following command at the command line prompt:
      npm install -g typescript

      The -g key makes the transpiler run in the global mode. Because the installation is performed through NPM, the TypeScript transpiler is installed in the npm folder. Make sure this parent folder is added to the PATH variable. This enables you to launch the transpiler from any folder.

      For more details on the NPM operation modes, see npm documentation. For more information about installing the TypeScript transpiler, see https://npmjs.org/package/typescript.

  • Run NPM from IntelliJ IDEA using the Node.js and NPM page of the Settings dialog box.
    1. Open the project settings and then click Node.js and NPM.
    2. On the Node.js and NPM page that opens, the Packages area shows all the Node.js-dependent packages that are currently installed on your computer, both at the global and at the project level. Click add.
    3. In the Available Packages dialog box that opens, select the typescript package.
    4. Select the Options check box and type -g in the text box next to it.
    5. Optionally specify the product version and click Install Package to start installation.

Installing the TypeScript transpiler in a project

  • Run the installation from the command line:
    1. Launch the embedded Terminal by hovering your mouse pointer over show_tool_window_bars in the lower left corner of IntelliJ IDEA and choosing Terminal from the menu (see Working with Embedded Local Terminal for details).
    2. Switch to the project root folder and type the following command at the command line prompt:
      npm install typescript
  • Run NPM from IntelliJ IDEA using the Node.js and NPM page of the Settings dialog box.
    1. Open the project settings by choosing File | Settings or pressing Ctrl+Alt+S, see Accessing Settings for details. Then click Node.js and NPM under the Languages & Frameworks node.
    2. On the Node.js and NPM page that opens, the Packages area shows all the Node.js-dependent packages that are currently installed on your computer, both at the global and at the project level. Click add.
    3. In the Available Packages dialog box that opens, select the required package.
    4. Optionally specify the product version and click Install Package to start installation.

Creating a File Watcher

  1. To start creating a File Watcher, open the Project Settings by choosing File | Settings on the main menu, and then click File Watchers. The File Watchers page that opens, shows the list of File Watchers that are already configured in the project.
  2. Click the Add button new.png or press Alt+Insert and choose the TypeScript predefined template from the pop-up list.
  3. In the Program text box, specify the path to the executable file (e.g. tsc.cmd). Type the path manually or click the Browse button browseButton.png and choose the file location in the dialog box that opens.
  4. Proceed as described on page Using File Watchers.

Transpiling the code

When you open a TypeScript file, IntelliJ IDEA checks whether an applicable file watcher is available in the current project. If such file watcher is configured but disabled, IntelliJ IDEA displays a pop-up window that informs you about the configured file watcher and suggests to enable it.

If an applicable file watcher is configured and enabled in the current project, IntelliJ IDEA starts it automatically upon the event specified in the New Watcher dialog.

  • If the Immediate file synchronization check box is selected, the File Watcher is invoked as soon as any changes are made to the source code.
  • If the Immediate file synchronization check box is cleared, the File Watcher is started upon save ( File | Save All , Ctrl+S) or when you move focus from IntelliJ IDEA (upon frame deactivation).

The transpiler stores the generated output in a separate file. The file has the name of the source TypeScript file and the extension js or js.map depending on the transpiler type. The location of the generated files is defined in the Output paths to refresh text box of the New Watcher dialog. Based on this setting, IntelliJ IDEA detects the transpiler output. However, in the Project Tree, they are shown under the source .ts file which is now displayed as a node.

See Also

Last modified: 12 November 2014
comments powered by Disqus