nvim-cmp/lua/cmp/config/mapping.lua

local mapping = setmetatable({}, {
  __call = function(_, invoke, modes)
    return {
      invoke = function(...)
        invoke(...)
      end,
      modes = modes or { 'i' },
    }
  end,
})

---Invoke completion
mapping.complete = function()
  return function(fallback)
    if not require('cmp').complete() then
      fallback()
    end
  end
end

---Close current completion menu if it displayed.
mapping.close = function()
  return function(fallback)
    if not require('cmp').close() then
      fallback()
    end
  end
end

---Abort current completion menu if it displayed.
mapping.abort = function()
  return function(fallback)
    if not require('cmp').abort() then
      fallback()
    end
  end
end

---Scroll documentation window.
mapping.scroll_docs = function(delta)
  return function(fallback)
    if not require('cmp').scroll_docs(delta) then
      fallback()
    end
  end
end

---Select next completion item.
mapping.select_next_item = function(option)
  return function(fallback)
    if not require('cmp').select_next_item(option) then
      fallback()
    end
  end
end

---Select prev completion item.
mapping.select_prev_item = function(option)
  return function(fallback)
    if not require('cmp').select_prev_item(option) then
      fallback()
    end
  end
end

---Confirm selection
mapping.confirm = function(option)
  return function(fallback)
    if not require('cmp').confirm(option) then
      fallback()
    end
  end
end

return mapping