Lazy loading plugins with vim.pack

Neovim 0.12 will have a built-in plugin manager, allowing for a simple and effective solution for managing external plugins. This will be a welcome addition for those who don’t need the complexity and extra features that come with popular plugin managers like lazy.nvim.

While vim.pack doesn’t have a built-in mechanism for lazy-loading, Neovim’s native event handling functionality can be used to lazy load plugins. For example, load nvim-treesitter just before a file gets loaded into the buffer:

vim.api.nvim_create_autocmd("BufReadPre", {
  once = true,
  callback = function()
    vim.pack.add({
      { src = "https://github.com/nvim-treesitter/nvim-treesitter", version = "main" },
    })
  end
})

Similarly for plugins which require a setup() call, this can also be added to the autocmd:

vim.api.nvim_create_autocmd("InsertEnter", {
  once = true,
  callback = function()
    vim.pack.add({ "https://github.com/nvim-mini/mini.pairs" })
    require("mini.pairs").setup()
  end
})

In this example mini.pairs will only be loaded when entering insert mode.

Another approach is to defer loading a plugin to just after startup using vim.schedule():

local opts = { ... }

vim.schedule(function()
  vim.pack.add({ "https://github.com/ibhagwan/fzf-lua" })
  require("fzf-lua").setup(opts)
end)

For plugins which are only required for certain filetypes, their vim.pack calls can be added to after/ftplugin/. For example, I only use custom snippets in LaTeX, so in after/ftplugin/tex.lua I have:

vim.api.nvim_create_autocmd("InsertEnter", {
  once = true,
  callback = function()
    vim.pack.add({"https://github.com/nvim-mini/mini.snippets"})
    require("mini.snippets").setup {
      snippets = {
        require('mini.snippets').gen_loader.from_lang(),
      },
      mappings = {
        expand = '<C-j>',
        jump_next = '<C-j>',
        jump_prev = '<C-k>',
        stop = '<C-c>',
      },
    }
  end
})

NOTE: some plugins handle filetype specific loading internally so loading them in ftplugin or after/ftplugin may lead to unwanted issues.