Set a Neovim key mapping to run `rush build` in a Rush monorepo.

keymap.lua

-- Run rush build for the package containing the current buffer
keymap.set("n", "<leader>b", function()
	local rush_root = vim.fs.find({ "rush.json" }, {
		path = vim.api.nvim_buf_get_name(0),
		upward = true,
	})[1]
	if not rush_root then
		vim.print("No rush.json found. Ostensibly not a Rush project.")
		return
	end
	local rush_root_dir = vim.fn.fnamemodify(rush_root, ":p:h")

	-- Get path of the current buffer
	local package_json = vim.fs.find({ "package.json" }, {
		path = vim.api.nvim_buf_get_name(0),
		upward = true,
		stop = rush_root,
	})[1]

	local target_options = ""
	if package_json then
		local package_dir = vim.fs.dirname(package_json)

		if package_dir == rush_root_dir then
			vim.print("No package.json found. Building the entire project.")
		else
			local package_name = vim.fs.basename(package_dir)
			target_options = " --to=" .. package_name
		end
	end

	-- Depends on `tslime` for this `Tmux` command
	vim.cmd.Tmux("rush build" .. target_options)
end, { silent = true })