VS Code Extension

Capabilities:

• look - theming

• custom components & views - extending workbench

• webview

• language extensions

• debugger extension

API Reference:

• https://code.visualstudio.com/api/references/vscode-api

Manifest:

• package.json (https://code.visualstudio.com/api/references/extension-manifest )

• most important fields:

  • name and publisher: VS Code uses <publisher>.<name> as a unique ID for the extension. For example, the Hello World sample has the ID vscode-samples.helloworld-sample. VS Code uses the ID to uniquely identify your extension

  • main: The extension entry point.

  • activationEvents and contributes: Activation Events and Contribution Points.

  • engines.vscode: This specifies the minimum version of VS Code API that the extension depends on.

Extension Entry:

• provides two functions:

  • activate

  • deactivate

VS Code UI

https://code.visualstudio.com/api/references/extension-guidelines

JSON declarations:

• where: "activationEvents" of package.json

• reference: https://sites.google.com/d/1ij93fOuJytaK6V_IAFJVgPC80u8URmkb/p/1_XI5uG6Rk1y4d-LJeFGgdKz4PUohTlOc/edit

Example:

"activationEvents": [

"onCommand:helloworld.helloWorld" // a command in contributions.commands

],

JSON declarations:

• where: "contributes" field in package.json

Commands:

• shows:

  • Command Palette (show category, no icon, no disabled command)

  • editor context menu (show disabled items, no category)

  • emit activationEvent "onCommand: ${command}"

• Consists of: id, title, icon, category, enablement (when clause https://code.visualstudio.com/api/references/when-clause-contexts )

Configuration & configurationDefaults:

• expose configuration keys -

  • able to set in user settings / workspace settings

  • use settings UI or JSON

• configurationDefaults - contributes default editor configurations to language

Custom Editors

Menus

Views

API Patterns:

• Cancellation tokens - for operations on volatile state that may change before finish, hence can check and get noticed when cancellation occurs

• Disposables - (like Java try-with-resources syntax)

• Events - onVerbNoun pattern methods

workspace.findFiles:

• glob:

  • when using absolute glob (string), return Url results from all workspace folders

  • use workspace.getWorkspaceFolder(url) to obtain the workspace folder {uri, name,index}

• define command:

  • in "contributes" "commands"

  • give it at least ID and title

• register activation on command

  • in "activationEvents"

  • "onCommand:" + ID

• in main, provide activate function

  • export function activate(context: vscode.ExtensionContext) {

  • use API vscode.commands.registerCommand to register handler, return a "disposable"

  • add the disposable to "context.subscriptions" so when extension is deactivated, disposable can be disposed