nvim-compe not working

init.lua

-- Neovim config

-- Completion

-- Source plugin (nvim-compe, folder name is 'completion')
vim.opt.runtimepath = vim.opt.runtimepath + '~/.local/share/nvim/plugins/completion'

vim.opt.completeopt = "menuone,noselect"

require'compe'.setup {
  enabled = true,
  autocomplete = true,
  debug = false,
  min_length = 1,
  preselect = 'enable',
  throttle_time = 80,
  source_timeout = 200,
  incomplete_delay = 400,
  max_abbr_width = 100,
  max_kind_width = 100,
  max_menu_width = 100,
  documentation = false,
  source = {
    path = true,
    buffer = true,
    calc = true,
    -- vsnip = true,
    -- nvim_lsp = true,
    -- nvim_lua = true,
    -- spell = true,
    -- tags = true,
    -- snippets_nvim = true,
    -- treesitter = true,
  },
}

local t = function(str)
  return vim.api.nvim_replace_termcodes(str, true, true, true)
end

local check_back_space = function()
    local col = vim.fn.col('.') - 1
    if col == 0 or vim.fn.getline('.'):sub(col, col):match('%s') then
        return true
    else
        return false
    end
end

-- Use (s-)tab to:
--- move to prev/next item in completion menuone
--- jump to prev/next snippet's placeholder
_G.tab_complete = function()
  if vim.fn.pumvisible() == 1 then
    return t "<C-n>"
  elseif check_back_space() then
    return t "<Tab>"
  else
    -- Does prints 'comp', when key pressed.
    print('comp')
    return vim.fn['compe#complete']()
  end
end

_G.s_tab_complete = function()
  if vim.fn.pumvisible() == 1 then
    return t "<C-p>"
  else
    -- If <S-Tab> is not working in your terminal, change it to <C-h>
    return t "<S-Tab>"
  end
end

vim.api.nvim_set_keymap("i", "<Tab>", "v:lua.tab_complete()", {expr = true})
vim.api.nvim_set_keymap("i", "<S-Tab>", "v:lua.s_tab_complete()", {expr = true})
vim.api.nvim_set_keymap("s", "<Tab>", "v:lua.tab_complete()", {expr = true})
vim.api.nvim_set_keymap("s", "<S-Tab>", "v:lua.s_tab_complete()", {expr = true})