Installing npm packages using bun

[jay-babu]

Hello,

https://github.com/williamboman/mason.nvim/blob/main/lua/mason-registry/index/typescript-language-server/init.lua. tsserver is installed using npm, which is probably preferred as it is stable. However there have been reports of big performance gains when using tsserver installed via bun, see reddit post. Is there a way to get npm packages installed via bun instead while still using mason?

[williamboman]

Hey, interesting! So installing "npm" packages via bun will not be considered with the rationale that installation of packages are normally done pretty infrequently via Mason. Furthermore all installations of npm packages are very simple (1 or 2 packages at most). As such, the room for meaningful perf gains from using Bun for package installation is relatively small.

As for running installed packages via bun instead of node, I think you should be able to do something like

lspconfig.tsserver.setup {
  cmd = { "bun", "run", "--bun", "typescript-language-server", "--stdio" }
}

This should execute the typescript-language-server executable provided by Mason in the Bun runtime.

I don't believe Bun has full parity with Node.js yet, so use at own risk!

[williamboman]

I think I'd be open for a PR to mason-lspconfig.nvim that adds this a setting and modifies CMDs accordingly (my only qualm is that I think such a feature would more appropriately belong in nvim-lspconfig, but I doubt they'd want to include something like that).

[williamboman]

Actually scratch that, adding it to mason-lspconfig.nvim would be too much of a scope creep. This would be a pretty easy plugin ^{(cough bunify.nvim)} to write though:

local util = require "lspconfig.util"

local function prefix_bun(cmd)
    return vim.list_extend({
        "bun",
        "run",
        "--bun",
    }, cmd)
end

util.on_setup = util.add_hook_before(util.on_setup, function(config, user_config)
    if config.cmd and is_node_server(config.name) then
        config.cmd = prefix_bun(config.cmd)
    end
end)

Note that the above probably will be problematic on Windows because how lspconfig prefixes these cmd's with cmd.exe /C.

[sljeff]

I tried to modify the lsp cmd, but the compatibility of bun is so poor that typescript-language-server cannot run successfully.