CoffeeScript for Zed

A lightweight Zed extension that adds CoffeeScript support:

• Syntax highlighting via a Tree‑sitter CoffeeScript grammar
• LSP features (completion, hover, diagnostics, etc.) via CoffeeSense

Requirements

• Zed editor
• Node.js and npm (for running the CoffeeSense language server via npx)
• Rust toolchain (only needed when you build the extension locally)

Language Server (CoffeeSense)

This extension runs CoffeeSense through npx so contributors don’t need a global install.

Configured in extension.toml:

[language_servers.coffeesense]
name = "CoffeeSense"
languages = ["CoffeeScript"]
command = "npx"
args = ["-y", "coffeesense-language-server@latest", "--stdio"]

Notes:

• -y accepts prompts; first run may download the package.
• You can pin a version for stability, e.g. "coffeesense-language-server@1.x".
• If npx is not on Zed’s PATH, set command = "/usr/bin/env" and args = ["npx", ...].

Grammar

The grammar is defined in extension.toml under [grammars.coffeescript]. It requires a Tree-sitter CoffeeScript grammar repository tree-sitter-coffeescript.

To have syntax highlighting and parsing work you need to clone the grammar locally or point to a public repo. Currently it points to a local checkout path.

Clone the Tree-sitter CoffeeScript grammar and set the local path in extension.toml:

[grammars.coffeescript]
repository = "file:///path/to/your/tree-sitter-coffeescript"
rev = "[latest commit hash]"

After public release this will be updated to use a public repo URL pinned rev, for example:

[grammars.coffeescript]
repository = "<git URL to your tree-sitter-coffeescript>"
rev = "<pinned commit>"

Developing / Installing Locally

• Open Zed and use the command palette: “Extensions: Install Dev Extension”. Choose coffeescript-zed folder and Zed will build and load the extension from source.
• Or build manually with Rust (Zed will still handle loading the built artifact when installing the dev extension):
  • cargo build --release

Troubleshooting

• CoffeeSense doesn’t start: ensure npx is on PATH for Zed. Try setting command = "/usr/bin/env" and args = ["npx", ...] as noted above.
• First-run is slow: npx may download CoffeeSense on first use; subsequent runs are cached.
• Grammar not loading on another machine: point [grammars.coffeescript] to a public repo/commit, or vendor the precompiled coffeescript.wasm as described.

More Information

Zed extension development docs: https://zed.dev/docs/extensions/developing-extensions