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Languages and frameworks: JavaScript

Last modified: 08 June 2023

Required plugin:

Javascript and TypeScript -  The plugin is bundled with JetBrains Rider and enabled by default.

With JetBrains Rider, you can develop modern web, mobile, and desktop applications with JavaScript and Node.js.

JetBrains Rider also supports React, Angular, Vue.js, and other frameworks and provides tight integration with various tools for web development.

JavaScript-aware coding assistance includes completion for keywords, labels, variables, parameters, and functions, error and syntax highlighting, formatting, code inspections and quick-fixes, as well as common and JavaScript-specific refactoring. JetBrains Rider also integrates with JavaScript linters and the Flow type checker.

With the built-in debugger, you can debug both your client-side and server-side code and even run JavaScript code snippets in the interactive debugger console. Note that JetBrains Rider supports debugging JavaScript only in Chrome or any other browser of the Chrome family. Learn more from Debug JavaScript in Chrome.

JetBrains Rider integrates with Jest, Karma, Protractor, Cucumber, and Mocha testing frameworks. JetBrains Rider supports running and debugging tests as well as navigation between tests and subjects or between a failed test and the fragment of code that caused the problem.

To open an application that is organized in the directory structure and does not have a solution file, press Ctrl+O or choose from the main menu, and then specify the root folder of the application.

Before you start

Make sure the JavaScript and TypeScript plugin is enabled in the settings. Press Ctrl+Alt+S to open the IDE settings and select Plugins. Click the Installed tab. In the search field, type JavaScript and TypeScript. For more details about plugins, see Managing plugins.

Choose the JavaScript language version

To get reliable and efficient coding assistance, you need to specify the language version that will be used in all JavaScript files of your project by default.

Using multiple JavaScript versions

If you are working on an application that uses both ECMAScript 5.1 and a newer version of ECMAScript, the easiest way is to choose the highest language version for the whole project from the list on the JavaScript page.

JSX syntax in JavaScript code

If you are using JSX syntax in your JavaScript code, enable ECMAScript 6+.

Download project dependencies

If your application uses some tools, libraries, or frameworks, download the required packages. To manage your project dependencies, you can use npm, Yarn 1, or Yarn 2, see npm and Yarn for details.

Install a package in an empty project

  • In the embedded Terminal (Ctrl+`) , type:

    npm install <package name>.

If you already have a package.json file in your project

  • Right-click the package.json file in the editor or in the Project tool window and choose Run 'npm install' from the context menu.

  • Alternatively, run npm install in the Terminal Ctrl+`.

note

Before you start, make sure you have Node.js on your computer.

Configure code completion for project dependencies

To provide code completion for project dependencies, JetBrains Rider automatically creates a node_modules library. In context of the language and the IDE, a library is a file or a set of files. Functions and methods of these files are added to JetBrains Rider's internal knowledge in addition to the functions and methods that JetBrains Rider retrieves from the project code that you edit.

View inlay hints

Inlay hints appear in the editor and provide you with additional information about your code to make it easier to read and navigate.

Parameter hints

Parameter hints show the names of parameters in methods and functions to make your code easier to read. By default, parameter hints are shown only for values that are literals or function expressions but not for named objects.

Parameter hints in JavaScript

Configure parameter hints

  1. Open the Settings/Preferences dialog (Ctrl+Alt+S) and go to Editor | Inlay Hints.

  2. Expand JavaScript under Parameter names.

  3. Specify the context in which you want parameter hints shown by selecting the corresponding checkboxes.

    The preview shows how the changes you make in the settings affect the code appearance.

  4. For some methods and functions, JetBrains Rider does not show parameter hints in any context. Click Exclude list... to view these methods and functions, possibly enable parameter hints for them, or add new items to the list.

  5. To hide parameter hints for any value type in any context, clear the JavaScript checkbox under Parameter names.

Return type hints

JetBrains Rider can display function return types in function calls and call chains.

  • Function return type hints are inferred from a JSDoc comment or based on the static analysis of your code.

  • Return type hints in method chains are displayed if the method calls are split between multiple lines and return at least 2 different types.

Configure method return type hints

  1. Open the Settings/Preferences dialog (Ctrl+Alt+S) and go to Editor | Inlay Hints.

  2. Under Types, expand the JavaScript node, and then select the Function return types checkbox.

  3. To show return type hints in method chains, expand the Method chains node and select the JavaScript checkbox.

The preview shows how the changes you make in the settings affect the code appearance.

Type hints

Type hints show the types of variables, fields, or parameters. The types of variables and fields are displayed to their definition. Type hints for parameters are shown in function calls. Type hints are inferred from JSDoc comments or static analysis of your code.

Type annotations in JavaScript

Configure type annotations

  1. Open the Settings/Preferences dialog (Ctrl+Alt+S) and go to Editor | Inlay Hints.

  2. In the tree of categories, expand Types | JavaScript.

  3. Expand the Type annotations node and specify the context where you want type hints to be shown.

    The preview shows how the changes you make in the settings affect the code appearance.

    JavaScript type annotation

  4. To hide parameter parameter type and return type hints for any value type in any context, clear the JavaScript checkbox under Types.

Auto-import in JavaScript

JetBrains Rider can generate import statements for modules, classes, components, and any other symbols that are exported. JetBrains Rider can add missing import statements on the fly, when you complete ES6 symbols or CommonJS modules. JetBrains Rider either decides on the style of the import statement itself or displays a popup where you can choose the style you need.

Add ES6 import statements

If you are importing a symbol from your project into a file that is a ES6 module or that already contains ES import statements, JetBrains Rider automatically inserts an ES6 import on symbol completion.

For earlier JavaScript versions or when auto-import on completion is disabled, JetBrains Rider marks the symbol as unresolved and shows a tooltip with the suggested quick-fix:

Auto import with quick-fix: information tooltip

Alternatively, press Alt+Enter:

Auto import with quick-fix: suggestion list

If there's more than one possible source of import, JetBrains Rider shows a list of suggestions:

Auto import with quick-fix: multiple choices

Learn more from Choosing the JavaScript language version.

JetBrains Rider can also generate import statements for symbols defined in the project’s dependencies. Auto-import works for symbols from packages that contain TypeScript definition files (like in moment or redux) or sources written as ES modules.

If the current file already contains a ES6 import statement, JetBrains Rider inserts a new one also in the ES6 style.

https://resources.jetbrains.com/help/img/rider/2023.1/ws_auto_import_from_node_modules.png
Gif

Add CommonJS (require) import statements

If you are importing a symbol from your project into a file that already is a CommonJS module (with a require statement or module.export), JetBrains Rider automatically inserts a CommonJS import on symbol completion.

https://resources.jetbrains.com/help/img/rider/2023.1/ws_js_auto_import_common_js.png
Gif

Alternatively, position the caret at the symbol to import, press Alt+Enter, and select a quick-fix with the CommonJS (require) import style.

Quick fix: select import style

note

Whenever JetBrains Rider cannot define automatically what syntax should be used in a file, it displays a popup where you can choose between using the ES6 and CommonJS syntax.

Configure auto import

Configure syntax highlighting

You can configure JavaScript-aware syntax highlighting according to your preferences and habits.

Run JavaScript in browser

Debug JavaScript

JetBrains Rider provides a built-in debugger for your client-side JavaScript code that works with Chrome or any other browser of the Chrome family. With JetBrains Rider, you can debug JavaScript applications running on the built-in server, on an external server, or on a remote server. For details, see Debug JavaScript in Chrome.