Update nvim/init.vim

nvim/init.vim

@@ -118,3 +118,18 @@ imap <C-j> <Plug>(coc-snippets-expand-jump)
 " Use <leader>x for convert visual selected code to snippet
 xmap <leader>x  <Plug>(coc-convert-snippet)
 
+" #####################################################
+" <Tab>: completion
+inoremap <silent><expr> <Tab>
+    \ pumvisible() ? "\<C-N>" :
+    \ s:check_back_space() ? "\<Tab>" :
+    \ coc#refresh()
+" <S-Tab>: completion back
+inoremap <silent><expr> <S-Tab> pumvisible() ? "\<C-P>" : "\<C-H>"
+" <CR>: confirm completion, or insert <CR>
+inoremap <expr> <CR> pumvisible() ? "\<C-Y>" : "\<CR>"
+
+function! s:check_back_space() abort
+    let col = col('.') - 1
+    return !col || getline('.')[col - 1] =~ '\s'
+endfunction