TypeScript in Visual Studio Code

TypeScript is a typed superset of JavaScript that compiles to plain JavaScript. It offers classes, modules, and interfaces to help you build robust components. The TypeScript language specification has full details about the language.

Installing the TypeScript compiler

Visual Studio Code includes TypeScript language support but does not include the TypeScript compiler, tsc. You will need to install the TypeScript compiler either globally or in your workspace to transpile TypeScript source code to JavaScript (tsc HelloWorld.ts).

The easiest way to install TypeScript is through npm, the Node.js Package Manager. If you have npm installed, you can install TypeScript globally (-g) on your computer by:

npm install -g typescript

You can test your install by checking the version.

tsc --version

Another option is to install the TypeScript compiler locally in your project (npm install --save-dev typescript) and has the benefit of avoiding possible interactions with other TypeScript projects you may have.

Syntax highlighting and semantic highlighting

In addition to syntax highlighting, TypeScript and JavaScript also provides semantic highlighting.

Syntax highlighting colors the text based on lexical rules. Semantic highlighting enriches the syntax coloring based on resolved symbol information from the language service.

Whether semantic highlighting is visible depends on the current color theme. Each theme can configure whether to display semantic highlighting and how it styles the semantic tokens.

If semantic highlighting is enabled and the color theme has a corresponding styling rule defined, different colors and styles can be seen.

Semantic highlighting can change colors based on:

• The resolved type of a symbol: namespace, variable, property, variable, property, class, interface, typeParameter.
• Whether the variable/property is read-only (const) or modifiable.
• Whether the variable/property type is callable (a function type) or not.

IntelliSense

IntelliSense shows you intelligent code completion, hover info, and signature information so that you can write code more quickly and correctly.

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VS Code provides IntelliSense for individual TypeScript files as well as TypeScript tsconfig.json projects.

Snippets

VS Code includes basic TypeScript snippets that are suggested as you type;

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You can install extensions to get additional snippets or define your own snippets for TypeScript. See User Defined Snippets for more information.

Tip: You can disable snippets by setting editor.snippetSuggestions to "none" in your settings file. If you’d like to see snippets, you can specify the order relative to suggestions; at the top ("top"), at the bottom ("bottom"), or inlined ordered alphabetically ("inline"). The default is "inline".

JSDoc support

VS Code’s TypeScript IntelliSense understands many standard JSDoc annotations, and uses them to show typing information and documentation in suggestions, hover info, and signature help.

Keep in mind that when using JSDoc for TypeScript code, you should not include type annotations. The TypeScript compiler only uses TypeScript type annotations and ignores those from JSDoc.

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To disable JSDoc comment suggestions in TypeScript, set "typescript.suggest.completeJSDocs": false.

Hover information

Hover over a TypeScript symbol to quickly see its type information and relevant documentation:

You can also show the hover info at the current cursor position with the kb(editor.action.showHover) keyboard shortcut.

Signature help

As you write a TypeScript function call, VS Code shows information about the function signature and highlights the parameter that you are currently completing:

Signature help is shown automatically when you type a ( or , within a function call. Use kb(editor.action.triggerParameterHints) to manually trigger signature help.

Auto imports

Automatic imports speed up coding by helping you find available symbols and automatically adding imports for them.

Just start typing to see suggestions for all available TypeScript symbols in your current project.

If you choose one of the suggestions from another file or module, VS Code will automatically add an import for it. In this example, VS Code adds an import for Hercules to the top of the file:

You can disable auto imports by setting "typescript.autoImportSuggestions.enabled": false.

Formatting

VS Code includes a TypeScript formatter that providers basic code formatting with reasonable defaults.

Use the typescript.format.* settings to configure the built-in formatter, such as making braces appear on their own line. Or, if the built-in formatter is getting in the way, set "typescript.format.enable" to false to disable it.

For more specialized code formatting styles, try installing one of the formatting extensions from the VS Code marketplace.

JSX and auto closing tags

VS Code’s TypeScript features also work with JSX. To use JSX in your TypeScript, use the *.tsx file extension instead of the normal *.ts:

VS Code also includes JSX-specific features such as autoclosing of JSX tags in TypeScript:

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Set "typescript.autoClosingTags" to false to disable JSX tag closing.

Code navigation

Code navigation lets you quickly navigate TypeScript projects.

• Go to Definition kb(editor.action.revealDefinition) - Go to the source code of a symbol definition.
• Peek Definition kb(editor.action.peekDefinition) - Bring up a Peek window that shows the definition of a symbol.
• Go to References kb(editor.action.goToReferences) - Show all references to a symbol.
• Go to Type Definition kb(editor.action.goToTypeDefinition) - Go to the type that defines a symbol. For an instance of a class, this will reveal the class itself instead of where the instance is defined.
• Go to Implementation kb(editor.action.goToImplementation) - Go to the implementations of an interface or abstract method.

You can navigate via symbol search using the Go to Symbol commands from the Command Palette (kb(workbench.action.showCommands)).

• Go to Symbol in File kb(workbench.action.gotoSymbol)
• Go to Symbol in Workspace kb(workbench.action.showAllSymbols)

Rename

Press kb(editor.action.rename) to rename the symbol under the cursor across your TypeScript project:

Refactoring

VS Code includes some handy refactorings for TypeScript such as Extract function and Extract constant. Just select the source code you’d like to extract and then click on the lightbulb in the gutter or press (kb(editor.action.quickFix)) to see available refactorings.

See Refactorings for more information about refactorings and how you can configure keyboard shortcuts for individual refactorings.

Available TypeScript refactorings include:

• Extract to method or function - Extract the selected statements or expressions to either a new method or a new function in the file.

  

  After selecting the Extract to method or Extract to function refactoring, enter the name of the extracted method/function.

• Extract to constant - Extract the selected expression to a new constant in the file.

  

• Extract type to interface or type alias - Extract the selected complex type to either an interface or a type alias.

  

• Move to new file - Move one or more classes, functions, constants, or interfaces in the top-level scope of the file to a new file. The new file’s name is inferred from the selected symbol’s name.

  

• Convert between named imports and namespace imports - Convert between named imports (import { Name } from './foo') and namespace imports (import * as foo from './foo').

  

• Convert between default export and named export - Convert from using a export default and having a named export (export const Foo = ...).

• Generate get and set accessors - Encapsulate a selected class property by generating a getter and setter for it.

  

• Convert parameters to destructured object - Rewrite a function that takes a long list of arguments to take a single arguments object.

Quick Fixes

Quick Fixes are suggested edits that address simple coding errors. Example Quick Fixes include:

• Adding a missing this to a member access.
• Fixing a misspelled property name.
• Removing unreachable code or unused imports
• Declaring

When you move your cursor on to a TypeScript error, VS Code shows a lightbulb that indicates that Quick Fixes are available. Click the lightbulb or press kb(editor.action.quickFix) to show a list of available Quick Fixes and refactorings.

Unused variables and unreachable code

Unused TypeScript code, such as the else block of an if statement that is always true or an unreferenced import, is faded out in the editor:

You can quickly remove this unused code by placing the cursor on it and triggering the Quick Fix command (kb(editor.action.quickFix)) or clicking on the lightbulb.

To disable fading out of unused code, set "editor.showUnused" to false. You can also disable fading of unused code only in TypeScriptScript by setting:

"[typescript]": {
    "editor.showUnused":  false
},
"[typescriptreact]": {
    "editor.showUnused":  false
},

Organize Imports

The Organize Imports source code action sorts the imports in a TypeScript file and removes unused imports:

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You can run Organize Imports from the Source Action context menu or with the kb(editor.action.organizeImports) keyboard shortcut.

Organize imports can also be automatically when you save a TypeScript file by setting:

"editor.codeActionsOnSave": {
    "source.organizeImports": true
}

Code suggestions

VS Code automatically suggests some common code simplifications such as converting a chain of .then calls on a promise to use async and await

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Set "typescript.suggestionActions.enabled" to false to disable suggestions.

References CodeLens

The TypeScript references CodeLens displays an inline count of reference for classes, interfaces, methods, properties, and exported objects:

You can enable this by setting "typescript.referencesCodeLens.enabled": true in the User Settings file.

Click on the reference count to quickly browse a list of references:

Implementations CodeLens

The TypeScript implementations CodeLens displays the number of implementors of an interface:

You can enable this by setting "typescript.implementationsCodeLens.enabled": true.

As with the references CodeLens, you can click on the implementation count to quickly browse a list of all implementations.

Update imports on file move

When you move or rename a file that is imported by other files in your TypeScript project, VS Code can automatically update all import paths that reference the moved file.

The typescript.updateImportsOnFileMove.enabled setting controls this behavior. Valid settings values are:

• "prompt" - The default. Asks if paths should be updated for each file move.
• "always" - Always automatically update paths.
• "never" - Do not update paths automatically and do not prompt.

Debugging

VS Code comes with great debugging support for TypeScript, including support for sourcemaps. Set breakpoints, inspect objects, navigate the call stack, and execute code in the Debug Console. See the Debugging topic to learn more.

Debug client side

You can debug your client-side code using a browser debugger such as Debugger for Chrome, Debugger for Edge or Debugger for Firefox.

Debug server side

Debug Node.js in VS Code using the built-in debugger. Setup is easy and there is a Node.js debugging tutorial to help you.

Linters

Linters provides warnings for suspicious looking code. While VS Code does not include a built-in TypeScript linter, TypeScript linter extensions available in the marketplace.

ESLint is a popular linter which also supports TypeScript. The ESLint extension integrates ESLint into VS Code so you can see linting errors right in the editor and even quickly many of fix them with Quick Fixes. The ESLint plugin guide details how to configure ESLint for your TypeScript projects.

TypeScript extensions

VS Code provides many features for TypeScript out of the box. In addition to what comes built-in, you can install an extension for greater functionality.

Tip: Click on an extension tile above to read the description and reviews to decide which extension is best for you. See more in the Marketplace.

Next steps

To learn more, see:

• TypeScript tutorial - Create a simple Hello World TypeScript in VS Code.
• Compiling TypeScript - Compile TypeScript to a JavaScript target version.
• Debugging TypeScript - Learn about debugging TypeScript both server and client-side with VS Code.

Common questions

Can I use the version of TypeScript that ships with VS 2015?

No, the TypeScript language service that ships with Visual Studio 2015 and 2017 isn’t compatible with VS Code. You will need to install a separate version of TypeScript from npm.

How can I use the latest TypeScript beta with VS Code?

The simplest way to try out the latest TypeScript features in VS Code is to install the JavaScript and TypeScript Nightly extension.

You can also configure VS Code to use a specific TypeScript version.