function! s:check_back_space() abort
  let col = col('.') - 1
  return !col || getline('.')[col - 1]  =~ '\s'
endfunction

inoremap <silent><expr> <Tab>
      \ pumvisible() ? "\<C-n>" :
      \ <SID>check_back_space() ? "\<Tab>" :
      \ coc#refresh()

" Navigating through results list
" Tab to select next result
inoremap <expr> <Tab> pumvisible() ? "\<C-n>" : "\<Tab>"
" Shift+Tab to select previous
inoremap <expr> <S-Tab> pumvisible() ? "\<C-p>" : "\<S-Tab>"
" Use enter to confirm completion
inoremap <expr> <cr> pumvisible() ? "\<C-y>" : "\<C-g>u\<CR>"
" Select first option if no option is selected on enter
inoremap <silent><expr> <cr> pumvisible() ? coc#_select_confirm() : "\<C-g>u\<CR>"