This repository contains a barebones local workspace VS Code extension named
Test Extension (TomasHubelbauer.test-extension).
Local workspace extensions are a VS Code feature where an extension can run off its source code directly, without needing to be installed from a VSIX or the VS Code extension marketplace.
This feature has been a part of VS Code since the version 1.89: https://code.visualstudio.com/updates/v1_89#_local-workspace-extensions
Local workspace extension needs to be installed once and VS Code will prompt you
to install it once it discovers it in the .vscode/extensions directory:
There is no need to add the extension to .vscode/extensions.json under the
recommendations key.
Once installed, VS Code will not prompt you to install it again and it will behave like any other regular VS Code extension.
By default, the extensions have an early-exit right at the entry point so they don't all file all the time. Remove it when testing out the test extension.
The local workspace extension gets refreshed whenever VS Code restarts, so any code changes will only take effect using the Cmd+Shift+P command palette command Developer: Reload Window.
I've filed a feature request for reloading local workspace extensions whenever a file belonging to a local workspace extension directory gets saved in VS Code: microsoft/vscode#229288
The extensions can make use of all VS Code extension APIs and they can read
both user and workspace settings (.vscode/setting.json).
See the VS Code extension API reference here: https://code.visualstudio.com/api/references/vscode-api
Local workspace VS Code extensions do not support ESM yet, there is a tracking ticket for this in the VS Code GitHub project: microsoft/vscode#130367
It relies on an internal VS Code dynamic loader and its support for ESM: microsoft/vscode-loader#36
For now, CJS' require and module.exports is used instead.
Other than ESM, what other ES features can be used is determined by the Node version bundled with VS Code as that is what the extension hose process runs on. You can find the Node version your install of VS Code uses by going to Code > About Visual Studio Code in the top bar of the window.
You may of course also opt to use a build process and enable your extensions to be written with ESM transpiled to CJS or in TypeScript transpiled to JavaScript for a better development extension traded in for setup simplicity.
Note that as of Node 22, there is experimental support for type stripping, allowing you to write your extensions in TypeScript whenever this feature becomes stable. There is no way to instruct the Node runtime used by the VS Code extension host to use extra CLI features to be able to opt into these experimental featues. https://nodejs.org/api/typescript.html#type-stripping
Problems with extension development can be debugged using the Ouput pane in the VS Code bottom panel under the Extension Host output channel.
This output channel will print errors that occured during the extension's activation:
[error] Activating extension TomasHubelbauer.test-extension failed due to an error:
[error] …/vscode-extension-playground/.vscode/extensions/test-extension/extension.js
…
In case there is no error, the extension will activate and log a success info:
[info] ExtensionService#_doActivateExtension TomasHubelbauer.test-extension, startup: false, activationEvent: 'onStartupFinished'
As it stands, this sample extensions displays an information message once it loads up and does nothing else:
I'm piling up more experiments in the repository for possible future reference. These extensions have their own readmes.
Be aware of the official extension samples repository by Microsoft: https://github.com/microsoft/vscode-extension-samples