Block all keys except hjkl in buffer

trap.lua

-- stylua: ignore

local function setup_buffer_keymaps(bufnr)
  -- Create buffer-local keymaps for 'h', 'j', 'k', 'l'
  local opts = { noremap = true, silent = true, buffer = bufnr }
  vim.keymap.set('n', 'h', '<cmd>echo "Pressed h"<CR>', opts)
  vim.keymap.set('n', 'j', '<cmd>echo "Pressed j"<CR>', opts)
  vim.keymap.set('n', 'k', '<cmd>echo "Pressed k"<CR>', opts)
  vim.keymap.set('n', 'l', '<cmd>echo "Pressed l"<CR>', opts)

  -- Define a function to close the buffer
  local close_buffer = function()
    vim.cmd('bwipeout!')
  end

  -- Map all printable keys (excluding 'hjkl')
  local keys = {
    'a', 'b', 'c', 'd', 'e', 'f', 'g', 'i', 'm', 'n', 'o', 'p', 'q', 'r', 's', 't',
    'u', 'v', 'w', 'x', 'y', 'z', 'A', 'B', 'C', 'D', 'E', 'F', 'G', 'I', 'M', 'N',
    'O', 'P', 'Q', 'R', 'S', 'T', 'U', 'V', 'W', 'X', 'Y', 'Z', '1', '2', '3', '4',
    '5', '6', '7', '8', '9', '0', '!', '@', '#', '$', '%', '^', '&', '*', '(', ')',
    '-', '_', '=', '+', '[', ']', '{', '}', ';', ':', "'", '"', ',', '.', '<', '>',
    '/', '?', '`', '~', '\\', '|', ' '
  }
  local special_keys = {
    '<CR>', '<Tab>', '<Esc>', '<Space>', '<BS>', '<Up>', '<Down>', '<Left>',
    '<Right>', '<Home>', '<End>', '<PageUp>', '<PageDown>', '<Insert>', '<Delete>'
  }

  -- Helper function to add mappings with modifiers
  local function add_mappings(keysmaps, modifiers)
    for _, key in ipairs(keysmaps) do
      vim.keymap.set('n', key, close_buffer, opts)
      for _, mod in ipairs(modifiers) do
        vim.keymap.set('n', mod .. key, close_buffer, opts)
      end
    end
  end

  -- Add mappings for normal keys
  add_mappings(keys, { '', '<C-', '<M-', '<A-' })

  -- Add mappings for special keys
  add_mappings(special_keys, { '', '<C-', '<M-', '<A-' })
end

-- Apply to the current buffer
setup_buffer_keymaps(0)