diff --git a/lua/cmp/core.lua b/lua/cmp/core.lua
index 047449c..3cc0400 100644
--- a/lua/cmp/core.lua
+++ b/lua/cmp/core.lua
@@ -15,7 +15,13 @@ local core = {}
 core.SOURCE_TIMEOUT = 500
 
 ---@type cmp.Menu
-core.menu = menu.new()
+core.menu = menu.new({
+  on_select = function(e)
+    for _, c in ipairs(e:get_commit_characters()) do
+      keymap.listen(c, core.on_keymap)
+    end
+  end,
+})
 
 ---@type table<number, cmp.Source>
 core.sources = {}
@@ -114,7 +120,7 @@ core.prepare = function()
 end
 
 ---Check auto-completion
-core.autocomplete = function(event)
+core.on_change = function(event)
   local ctx = core.get_context({ reason = types.cmp.ContextReason.Auto })
 
   -- Skip autocompletion when the item is selected manually.
diff --git a/lua/cmp/init.lua b/lua/cmp/init.lua
index 27ccfd4..b15935c 100644
--- a/lua/cmp/init.lua
+++ b/lua/cmp/init.lua
@@ -65,11 +65,11 @@ end
 ---Handle events
 autocmd.subscribe('InsertEnter', function()
   core.prepare()
-  core.autocomplete('InsertEnter')
+  core.on_change('InsertEnter')
 end)
 
 autocmd.subscribe('TextChanged', function()
-  core.autocomplete('TextChanged')
+  core.on_change('TextChanged')
 end)
 
 autocmd.subscribe('InsertLeave', function()
diff --git a/lua/cmp/menu.lua b/lua/cmp/menu.lua
index da1929d..bd1b85d 100644
--- a/lua/cmp/menu.lua
+++ b/lua/cmp/menu.lua
@@ -5,6 +5,9 @@ local types = require('cmp.types')
 local config = require('cmp.config')
 local autocmd = require('cmp.autocmd')
 
+---@class cmp.MenuOption
+---@field on_select fun(e: cmp.Entry)
+
 ---@class cmp.Menu
 ---@field public float cmp.Float
 ---@field public cache cmp.Cache
@@ -19,12 +22,13 @@ local autocmd = require('cmp.autocmd')
 local menu = {}
 
 ---Create menu
+---@param opts cmp.MenuOption
 ---@return cmp.Menu
-menu.new = function()
+menu.new = function(opts)
   local self = setmetatable({}, { __index = menu })
   self.float = float.new()
   self.resolve_dedup = async.dedup()
-  self.on_select = function() end
+  self.on_select = opts.on_select or function() end
   self:reset()
   autocmd.subscribe('CompleteChanged', function()
     local e = self:get_selected_entry()