---
description: VS Code coding guidelines — naming, style, types, strings, and code quality rules. Reference when writing or reviewing code.
applyTo: src/vs/**
---

# Coding Guidelines

Canonical reference: https://github.com/microsoft/vscode/wiki/Coding-Guidelines

Also see the [Source Code Organization](https://github.com/microsoft/vscode/wiki/Source-Code-Organization) wiki page.

## Indentation

Use tabs, not spaces.

## Naming

- PascalCase for types and enum values
- camelCase for functions, methods, properties, and local variables
- Use whole words when possible

## Types

- Do not export types or functions unless shared across multiple components
- Do not introduce new types or values to the global namespace

## Comments

- Use JSDoc style comments for functions, interfaces, enums, and classes

## Strings

- `"double quotes"` for user-visible strings that need localization
- `'single quotes'` for everything else
- All user-visible strings must be externalized via `nls.localize()` — no string concatenation, use `{0}` placeholders

## UI Labels

- Title case for command labels, buttons, and menu items (each major word capitalized)
- Don't capitalize prepositions of four or fewer letters unless first or last word
- Sentence case for view titles/headings (only first word capitalized), no trailing period

## Style

- Arrow functions over anonymous function expressions
- Only parenthesize arrow parameters when necessary: `x => x + x` not `(x) => x + x`
- Always surround loop and conditional bodies with curly braces
- Open curly braces on the same line
- No surrounding whitespace in parenthesized constructs
- Prefer `export function x(…) {…}` over `export const x = (…) => {…}` at top-level scope (better stack traces)

## Code Quality

- Include Microsoft copyright header in all files
- Prefer `async`/`await` over `Promise.then()`
- Localize all user-facing messages
- Prefer named regex capture groups over numbered ones
- Do not use `any` or `unknown` unless absolutely necessary
- Register disposables immediately after creation — use `DisposableStore`, `MutableDisposable`, or `this._register()`
- Declare service dependencies in constructors via DI — never access services through `IInstantiationService` elsewhere
- Use `IEditorService` to open editors, not `IEditorGroupsService.activeGroup.openEditor`
- Avoid `bind()`/`call()`/`apply()` solely for `this` — prefer arrow functions
- Avoid events for control flow between components — prefer direct method calls