Languages and frameworks
TypeScript

Languages and frameworks: TypeScript

Last modified: 09 June 2023

Required plugin:

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

JetBrains Rider supports developing, running, and debugging TypeScript source code. JetBrains Rider recognizes .ts and .tsx files and provides full range of coding assistance for editing them without any additional steps from your side. TypeScript files are marked with the icon.

TypeScript-aware coding assistance includes completion for keywords, labels, variables, parameters, and functions, error and syntax highlighting, formatting, numerous code inspections and quick-fixes, as well as common and TypeScript-specific refactoring. JetBrains Rider also verifies TypeScript code on the fly and shows errors in a dedicated Problems tool window.

Compilation errors are reported in the TypeScript tool window. Learn more from Compiling TypeScript into JavaScript.

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.

Verify TypeScript

JetBrains Rider verifies TypeScript code mainly based on the data from the TypeScript Language Service which also compiles TypeScript into JavaScript.

Descriptions of the errors detected in the current file and quick-fixes for them are available from the editor.

Verify TypeScript in the current file

In the editor, hover the mouse pointer over the highlighted problem. JetBrains Rider shows a tooltip with a description of the problem.
Apply the suggested quick-fix or click More actions and select the relevant one from the list.
Alternatively open the File tab of the Problems tool window Alt+6, where you can view problem descriptions, apply quick-fixes, navigate to the fragments in the source code where errors occurred, as well as fix them in the Editor Preview pane without leaving the tool window. Learn more from Problems tool window.

Verify TypeScript in the entire project

To open the Problems tool window, click the Inspections widget in the upper-right corner of the editor.

Alternatively select View | Tool windows | Problems from the main menu or press Alt+6.
Open the Project Errors tab, which shows the errors across the entire project, with error messages grouped by files in which they were detected.
Here you can view problem descriptions, apply quick-fixes, navigate to the fragments in the source code where errors occurred, as well as fix them in the Editor Preview pane without leaving the tool window. Learn more from Problems tool window.

note
Checking TypeScript code across the whole project is enabled by default. To turn it off, open the Settings/Preferences dialog (Ctrl+Alt+S), go to Languages and Frameworks | TypeScript, and clear the Show project errors checkbox in the TypeScript language service area.

Configure integration with the TypeScript Language Service

In most cases, everything works out of the box and no manual configuration is required. However, if you want to use a custom typescript package or pass some command-line options to the TypeScript Language Service, you can customize the default settings.

In the Settings/Preferences dialog (Ctrl+Alt+S), go to Languages & Frameworks | TypeScript.
Alternatively, click the TypeScript widget on the Status bar and select Configure TypeScript….
The TypeScript page opens.
Specify the Node.js interpreter to use.
If you choose the Project alias, JetBrains Rider will automatically use the project default interpreter from the Node interpreter field on the Node.js page . In most cases, JetBrains Rider detects the project default interpreter and fills in the field itself.
You can also choose another configured local or remote interpreter or click and configure a new one.
In the TypeScript field, specify the version of the TypeScript to use (JetBrains Rider displays the currently chosen version).
- By default, the typescript package from the project's node_modules folder is used.
- Bundled: choose this option to use the typescript package that is shipped with JetBrains Rider without attempting to find another one.
- Select: choose this option to use a custom typescript package instead of the one bundled with JetBrains Rider. In the dialog that opens, choose the path to the relevant package.
- If your project package manager is Yarn 2, you have to use the typescript package installed via Yarn 2. In this case, yarn:package.json:typescript is by default selected.
  Learn more about package managers from npm and Yarn.
Make sure the TypeScript Language Service checkbox is selected.
Use the controls below to configure the behaviour of the TypeScript Language Service.
In the Options field, specify the command-line options to be passed to the TypeScript Language Service when the tsconfig.json file is not found. See the list of acceptable options at TSC arguments. Note that the -w or --watch (Watch input files) option is irrelevant.

tip
You can enhance completion in JavaScript files with suggestions from the TypeScript Language Service. To do that, add 'allowJS' : true to your jsconfig.json or tsconfig.json file.

Restart the TypeScript Language Service

Click the TypeScript widget on the Status bar and select Restart TypeScript Service from the list.

Edit TypeScript code

JetBrains Rider brings you smart coding assistance for TypeScript including context-aware code completion, auto-import for symbols, documentation look-up, parameter hints, navigation, TypeScript-aware syntax highlighting and linting, refactoring and more.

Auto import

JetBrains Rider can generate import statements for modules, classes, components, and any other TypeScript symbols that are exported. By default, JetBrains Rider adds import statements when you complete TypeScript symbols.

When you type your code or paste a fragment with a symbol that is not yet imported, JetBrains Rider can also generate an import statement for this symbol. If there is only one source to import the symbol from, JetBrains Rider inserts an import statement silently. Otherwise, use an auto-import tooltip or a dedicated import quick-fix.

Add import statements on code completion

In the Settings/Preferences dialog (Ctrl+Alt+S), go to Editor | General | Auto Import. The Auto Import page opens.
In the TypeScript/JavaScript area, select the Add TypeScript imports automatically and On code completion checkboxes.

tip
To change the background color for auto-import tooltips, press Ctrl+Alt+S and go to Editor | Color Scheme | General | Popups and Hints | Question hints.

Add import statements on typing or pasting code

In the Settings/Preferences dialog (Ctrl+Alt+S), go to Editor | General | Auto Import. The Auto Import page opens.
In the TypeScript/JavaScript area, select the Add TypeScript imports automatically and Unambiguous imports on the fly checkboxes.

Use auto-import tooltips

If an import statement for a TypeScript symbol was not added on completion or editing, JetBrains Rider shows you a popup that suggests importing the symbol.

To accept the suggestion, press Alt+Enter:
If there's more than one possible source of import, JetBrains Rider informs you about that:
Pressing Alt+Enter in this case opens a list of suggestions:
To hide auto-import tooltips, open the Settings/Preferences dialog (Ctrl+Alt+S), go to Editor | General | Auto Import, and clear the With auto-import tooltip checkbox.

Use import quick-fixes

If an auto-import tooltip doesn't show up, you can always add an import statement via the dedicated quick-fix.

To generate an import, select Add import statement:
If there is only one source to import a symbol from, JetBrains Rider generates an import statement:
If there are several sources to import a symbol from, select the relevant one from the suggestion list:
If the TypeScript Language Service is enabled in your project, you can also use its suggestion:
If there are several sources to import a symbol from, select the relevant one from the list that the TypeScript Language Service shows:

Enable type auto imports

Open your tsconfig.json file and set the importsNotUsedAsValues flag in compilerOptions to error:
```
"importsNotUsedAsValues": "error",
```

Learn more from the typeScript official website.

Configure the appearance of import statements

In the Settings/Preferences dialog (Ctrl+Alt+S), go to Editor | Code Style | TypeScript, and use the controls in the Imports tab.

Documentation look-up

JetBrains Rider lets you get reference for symbols from your project and from its dependencies, for symbols defined in external libraries, and for standard JavaScript APIs because TypeScript implements all of them.

By default, documentation is shown in the Documentation popup but you can configure it to appear in the Documentation tool window.

Quick Documentation in a popup

Hover the mouse over the necessary symbol in the editor.
Place the caret at the symbol and press Ctrl+K, I or select View | Quick Documentation from the main menu.
For standard JavaScript methods available in TypeScript, JetBrains Rider also shows a link to the corresponding MDN article.
Press Ctrl+K, I again to open this documentation in the Documentation tool window.
Click in the popup to change the font size, display the quick documentation toolbar, or go to the source code.

note
To toggle the focus of the Quick Documentation popup and the Documentation Tool Window, press Ctrl+K, I sequentially.

Click in the popup to change the font size, display the quick documentation toolbar, or go to the source code.

Quick Documentation in the tool window

https://resources.jetbrains.com/help/img/rider/2023.1/ws_js_quick_doc_tool_window_706.png

With the default settings, pressing Ctrl+K, I (View | Quick Documentation) opens quick documentation in a popup. You can change the settings to view documentation in the tool window.

In the quick documentation popup, click and disable the Show Documentation Popup First option.
In the Documentation tool window, click the icon on the tool window toolbar and disable the Show Documentation Popup First option.

You can open a piece of documentation for a specific code element in the tool window and keep viewing documentation for other elements in your current file .

In the tool window, code documentation is displayed on the unpinned tab (the tab marked with the asterisk symbol (*). You can view this documentation by hovering over a symbol or placing the caret at it.

View the MDN documentation for a symbol at caret

In the Documentation window Ctrl+K, I, click the MDN link.
Alternatively, press Shift+F1 or choose View | External Documentation from the main menu.

JetBrains Rider opens the MDN article in the default JetBrains Rider browser.

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.

Configure parameter hints

Open the Settings/Preferences dialog (Ctrl+Alt+S) and go to Editor | Inlay Hints.
Expand TypeScript under Parameter names.
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.
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.
To hide parameter hints for any value type in any context, clear the TypeScript 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 function return type hints

Open the Settings/Preferences dialog (Ctrl+Alt+S) and go to Editor | Inlay Hints.
Under Types, expand the TypeScript node, and then select the Function return types checkbox.
To show return type hints in method chains, expand the Method chains node and select the TypeScript 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.

Configure type hints

Open the Settings/Preferences dialog (Ctrl+Alt+S) and go to Editor | Inlay Hints.
Expand Types | TypeScript.
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.
To hide parameter type and return type hints for any value type in any context, clear the TypeScript checkbox under Types.

Numeric enum values

By default, JetBrains Rider shows inferred values for numeric enums to make your code easier to read.

Hide numeric enum values

Open the Settings/Preferences dialog (Ctrl+Alt+S) and go to Editor | Inlay Hints.
Expand the Values node and select the TypeScript checkbox. JetBrains Rider will hide the inferred values and show only the values of explicitly initialized constants. The preview shows how the changes you make in the settings affect the code appearance.

JavaScript libraries in TypeScript

When working with JavaScript libraries in TypeScript, you need to install type declarations for them. JetBrains Rider reminds you to install them via npm or yarn and updates your package.json file accordingly.

Install the type declarations

Position the caret at the warning and press Alt+Enter.
Select the suggestion and press Enter.

Syntax highlighting

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

In the Settings/Preferences dialog (Ctrl+Alt+S), go to Editor | Color Scheme | TypeScript.
Select the color scheme, accept the highlighting settings inherited from the defaults or customize them as described in Colors schemes: fonts and colors of IDE text.

Code navigation

You can quickly navigate through your TypeScript project in the JetBrains Rider editor using different actions and popups.

Go to declaration of a symbol

You can navigate from a variable, a field, a method, or any other symbol to its declaration or view the symbol definition in a popup without jumping anywhere from the code you are editing.

To jump to the declaration of a symbol, place the caret at a usage of the symbol and press F12 or select Navigate | Declaration or Usages from the main menu.
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Alternatively, use Ctrl+Click: keeping Ctrl pressed, hover your mouse pointer over the symbol. When the symbol turns into a hyperlink, click the hyperlink without releasing Ctrl.
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To view the definition of a symbol in a popup, place the caret at its usage and press Alt+F12 or select View | Quick Definition from the main menu.

Go to usages of a symbol

You can view a list of usages of a symbol and select the one to jump to.

To get a list of usages of a symbol, place the caret at the declaration of the symbol and do one of the following:
- Press F12 or select Navigate | Declaration or Usages from the main menu.
- Press Alt+Shift+F12 or select Edit | Find Usages | Shows Usages from the main menu.
From the list, select the usage of the symbol where you want to jump.
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Go to type declaration of a symbol

You can navigate from a variable, a field, a method, or any other symbol to its type declaration. Alternatively, open the type definition in a popup without jumping to the type declaration.

JetBrains Rider also shows the inferred type of an object. You can view the inferred type information in a tooltip or in the documentation popup.

Jump to type declaration

To jump from a symbol to the declaration of its type, place the caret at a usage of the symbol and press Ctrl+Shift+F11 or select Navigate | Type Declaration from the main menu.
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To view the type definition of a symbol in a popup, place the caret at the symbol for which you want to view the type definition and select View | Quick Type Definition.
For an instance of a class, this will reveal the class itself instead of where this instance is defined.
tip
JetBrains Rider has no default keyboard shortcut for this action, but you can manually configure it as described in Adding keyboard shortcuts.

View inferred type information of a symbol

Hold Ctrl and hover the mouse pointer over the symbol.
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Alternatively, hover the mouse pointer over a symbol. JetBrains Rider immediately displays the reference for it in the Documentation popup.
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Learn more from Documentation look-up above.

Note the difference between Go To Declaration and Go To Type Declaration. Suppose you have a file app.ts with the following code:

import {Dog} from "./dog";

let dog = new Dog();
dog.bark();

If you place the caret at dog in dog.bark(), then Go To Declaration brings you to the declaration of the variable in let dog = new Dog (), while Go To Type Declaration brings you to the declaration of the class Dog.

Navigate between subclasses, superclasses, overrides, and implementations

You can keep track of class implementations and overriding methods either using the gutter icons in the editor or pressing the appropriate shortcuts.

Go to a subclass

Press Alt+End or click in the gutter and then select the relevant class from the list.
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Alternatively, select Navigate | Implementation(s) from the main menu or Go To | Implementation(s) from the context menu and then select the relevant class from the list.

Go to a superclass or overridden method

Place the caret at a subclass and press Alt+Home. JetBrains Rider brings you to the declaration of the superclass and positions the cursor at its name.
Click in the gutter next to an overriding method. JetBrains Rider brings you to the superclass with the cursor at the overridden method.
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Alternatively, place the caret at the overriding method and press Alt+Home or select Navigate | Super Method from the main menu or Go To | Super Method from the context menu.

Go to an interface or implemented method

Place the caret at an implementation of an interface, press Alt+Home, and select the interface to go to.
JetBrains Rider brings you to the declaration of the interface and positions the cursor at its name.
Click in the gutter next to the implementing method. JetBrains Rider brings you to the corresponding interface with the cursor at the implemented method.
Gif
Alternatively, place the caret at the implementing method and press Alt+Home or select Navigate | Super Method from the main menu or Go To | Super Method from the context menu.

Refactoring in TypeScript

JetBrains Rider provides both common refactoring procedures, such as rename/move, and so on, and TypeScript-specific refactoring procedures, such as change signature, introduce parameter, introduce variable.

Run and debug your application

With JetBrains Rider, you can run and debug client-side TypeScript code and TypeScript code running in Node.js. Learn more from Running and debugging TypeScript.

Languages and frameworks: TypeScript﻿

Before you start﻿

Verify TypeScript﻿

Verify TypeScript in the current file﻿

Verify TypeScript in the entire project﻿

note

Configure integration with the TypeScript Language Service﻿

tip

Restart the TypeScript Language Service﻿

Edit TypeScript code﻿

Auto import﻿

Add import statements on code completion﻿

tip

Add import statements on typing or pasting code﻿

Use auto-import tooltips﻿

Use import quick-fixes﻿

Enable type auto imports﻿

Configure the appearance of import statements﻿

Documentation look-up﻿

Quick Documentation in a popup﻿

note

Quick Documentation in the tool window﻿

View the MDN documentation for a symbol at caret﻿

View inlay hints﻿

Parameter hints﻿

Configure parameter hints﻿

Return type hints﻿

Configure function return type hints﻿

Type hints﻿

Configure type hints﻿

Numeric enum values﻿

Hide numeric enum values﻿

JavaScript libraries in TypeScript﻿

Install the type declarations﻿

Syntax highlighting﻿

Code navigation﻿

Go to declaration of a symbol﻿

Go to usages of a symbol﻿

Go to type declaration of a symbol﻿

Jump to type declaration﻿

tip

View inferred type information of a symbol﻿

Navigate between subclasses, superclasses, overrides, and implementations﻿

Go to a subclass﻿

Go to a superclass or overridden method﻿

Go to an interface or implemented method﻿

Refactoring in TypeScript﻿

Run and debug your application﻿