rescript-vscode

The official VSCode plugin for ReScript.

Prerequisite

You must have rescript >=9.1 or bs-platform >=8.3.3 installed locally in your project, through the usual npm installation. Older versions are not guaranteed to work.

Recommendation

Our highlighting works well with most popular VSCode themes, such as:

• Dark+ (default dark), Light+ (default light)
• Solarized Dark, Solarized Light
• Monokai Dimmed
• Tomorrow Night Blue
• One Dark Pro

The only 2 themes we don't (and can't) support, due to their lack of coloring, are:

• Dark (Visual Studio), Light (Visual Studio)

If your custom theme doesn't seem to highlight much (e.g. no colors for upper-case JSX tag, no distinction between module and variant), try one of the recommended themes to see if that's the problem. For more info, see this post.

Installation

The plugin's on VSCode Marketplace. In VSCode, cmd-shift-p -> "Install Extensions", then find "rescript-vscode".

The plugin activates on .res and .resi files. If you've already got Reason-Language-Server installed, it's possible that the latter took precedence over this one. Make sure you're using this plugin ("ReScript syntax") rather than Reason-Language-Server ("BuckleScript syntax").

Features

• Supports .res, .resi and bsconfig.json.
• Syntax highlighting.
• Formatting, with caveats:
  • Currently requires the file to be part of a ReScript project, i.e. with a bsconfig.json.
  • Cannot be a temporary file.
• Build diagnostics.
• Built-in bsb watcher (optional, and exposed explicitly as a pop-up; no worries of dangling build).
• Type hint hover.
• Jump to definition.
• Autocomplete.
• Find references.
• Rename.
• Snippets to ease a few syntaxes:
  • external features such as @bs.module and @bs.val
  • try, for, etc.
• Folding, and custom folding through //#region and //#endregion.

Experimental Features

Dead Code Analysis mode

Runs dead code analysis via reanalyze.

Usage

Open the command palette and run > ReScript: Start dead code analysis.. This will start dead code analysis in the ReScript project of the file you run the command from.

Dead code is highlighted in the editor, and code actions for suppressing dead code warnings are available in most cases.

When done, stop the dead code analysis mode by clicking the Stop Dead Code Analysis mode button in the editor status bar. This will clear all reported dead code warnings.

Note: This mode uses npx reanalyze to run the analysis binary. For reproducible results, install reanalyze with npm install reanalyze --save-dev.

Caveats

Currently does not work for full monorepo dead code analysis (although it should work for each monorepo package individually).

Use with Other Editors

This repo also contains a language server that can power other editors. However, the language server in this project is a pure implementation detail. We don't guarantee its stability for other editors' consumption apart from Vim and Sublime Text.

Still, if you'd like to use this language-server with other editors:

• Get the release binaries from the Github Releases page.
• Unzip the .vsix and get the server folder. That's the only folder you need.
• The language server will be at server/out/server.js. Call it through node, and optionally pass --stdio if your editor doesn't support the default JSONRPC.