TS++

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TS++ (ts-plus-plus, abbreviated TSPP) is an experimental language and compiler derived from TypeScript. This repository starts from the TypeScript 6.0.3 source tree and develops TS++ as a separate product while preserving TypeScript as its compatibility boundary.

The project grows through isolated feature capsules. Each feature owns its syntax, semantic analysis, language-service additions, and editor metadata; shared packages provide loading and narrow SDK contracts instead of accumulating feature branches in the TypeScript-derived core.

👉 Looking for existing features? Explore the TS++ Features & Plugin Catalog for a comprehensive overview of all 8 active feature capsules, syntax specifications, and status.

Repository layout

.
└─ packages/
   ├─ compiler/          # TypeScript-derived TS++ compiler and tsserver
   ├─ examples/          # One independently configured project per plugin set
   ├─ language-server/   # LSP adapter around the TSPP server protocol
   ├─ playground/        # Browser compiler with worker-isolated capsule sets
   ├─ plugin-sdk/        # Public contracts shared by isolated plugin packages
   ├─ plugins/           # One package per complete feature capsule
   └─ vscode-extension/  # VSCode client for the TSPP language server

Development

Use Node.js 22 and pnpm 12.4.2.

corepack enable
pnpm install
pnpm build
pnpm lint
pnpm test
pnpm playground:dev

Plugins written in .tspp build with the commit in scripts/bootstrap-pin.json. On a cache miss, pnpm bootstrap:install builds a compiler package from that commit in an isolated checkout. CI caches the package by commit, and local builds reuse it from the Git-ignored .bootstrap/ directory. Keep the seed commit reachable when updating the pin.

For local experiments, build the workspace compiler with pnpm build:compiler, then set TSPP_BOOTSTRAP=dev when building the plugin. This mode uses the workspace's built compiler and plugin outputs. In PowerShell, set it with $env:TSPP_BOOTSTRAP = 'dev' and clear it with Remove-Item Env:TSPP_BOOTSTRAP.

Commands

The compiler package exposes two commands:

• tspp — the TS++ command-line compiler;
• tsppserver — the TSPP compiler service using the upstream tsserver protocol.

The separate LSP package exposes tspp-language-server, which adapts that protocol to LSP. The VSCode extension starts the LSP with the workspace ts-plus-plus SDK and associates .tspp files with the tspp language mode.

Releases

A release publishes three things, all at the version of the root package.json: the ts-plus-plus package, the VS Code extension and the playground as a static site in a zip. Every other package in the workspace is internal, stays at 0.0.0 and is never published on its own:

• the feature plugins and the SDK travel inside ts-plus-plus as bundled dependencies. Projects name the plugins ts-plus-plus/plugins/<name>;
• the extension carries the language server.

The compiler package keeps the TypeScript version it implements as its own version in the repository. The released manifest records that version as typescriptVersion, which the language server reads to decide which TypeScript features to offer.

pnpm pack:release   # builds, then assembles release/
pnpm test:release   # installs release/ into an empty project and exercises it

Releasing is setting the version: when the TSPP checks pass on a commit pushed to master whose root version has no vX.Y.Z tag, .github/workflows/release.yml runs both commands above on that commit and publishes the result on GitHub Releases, which tags it. A version with a prerelease part, such as 0.2.0-beta.1, is published as a prerelease. A version below one already released fails the TSPP checks (scripts/release-version.mjs), so it never reaches a release. Nothing is published to npm or the Marketplace.

The steps, how to choose a version and what to do when a release fails are in docs/releasing.md.

Compiler extensions use @tspp/plugin-sdk. The SDK currently covers expression, statement, declaration and type syntax; source projection; asynchronous program analysis and artifacts; compile-time macros; semantic Quick Info; activation dependencies and static editor contributions. New ports are added only when a real feature demonstrates the boundary it needs.

Feature projects select capsules through compilerOptions.plugins. The host validates required and optional relationships, refuses plugins that claim the same syntax, activates capsules in dependency order, and keeps feature code out of the LSP and VS Code clients.

During repository development, build the compiler before invoking its generated outputs. The root scripts delegate to the ts-plus-plus workspace.

TypeScript compatibility boundary

TS++ deliberately retains upstream internal names such as the ts namespace, typescript.js, tsconfig.json, and the tsserver protocol. Those names describe the TypeScript API and compatibility surface, not the public TS++ product name. Keeping that boundary stable also makes future upstream comparison and merging tractable.

License and upstream notices

TS++ is distributed under the Apache License 2.0. The compiler package retains the upstream TypeScript license, security policy, and third-party notices.