`Ctrl+W` -> `]` に割り当て。`vsplit`コマンドを実行したあとに[[Nvim LSP client]]のコマンドを実行すればよい。
```lua
vim.api.nvim_create_autocmd("LspAttach", {
group = vim.api.nvim_create_augroup("UserLspConfig", {}),
callback = function(ev)
local opts = { buffer = ev.buf }
-- <C-w>] で開く
vim.keymap.set("n", "<C-w>]", function()
vim.cmd([[ vsplit ]])
vim.lsp.buf.definition()
end, opts)
```
## 参考
- [key bindings \- Shortcut to open definition of variable in a vertical split with Neovim mapping \- Vi and Vim Stack Exchange](https://vi.stackexchange.com/questions/42123/shortcut-to-open-definition-of-variable-in-a-vertical-split-with-neovim-mapping)