neovim/lua/plugins/file-tree.lua

-- disable netrw at the very start of your init.lua (strongly advised)
vim.g.loaded_netrw = 1
vim.g.loaded_netrwPlugin = 1

-- set termguicolors to enable highlight groups
vim.opt.termguicolors = true

-- OR setup with some options
require("nvim-tree").setup({
    auto_reload_on_write = true,
    sort_by = "case_sensitive",
    sync_root_with_cwd = true,
    respect_buf_cwd = true,
    update_focused_file = {
        enable = true,
        update_root = true,
    },
    filters = { custom = { ".git" } },
    view = {
        width = 30,
        mappings = {
            list = {
                { key = "u", action = "dir_up" },
            },
        },
    },
    renderer = {
        group_empty = true,
    },
})

local function open_nvim_tree(data)
    -- buffer is a directory
    local directory = vim.fn.isdirectory(data.file) == 1

    if not directory then
        return
    end

    -- change to the directory
    vim.cmd.cd(data.file)

    -- open the tree
    require("nvim-tree.api").tree.open()
end

vim.api.nvim_create_autocmd({ "VimEnter" }, { callback = open_nvim_tree })