simplify deferred open

lib/levelup.js

@@ -118,6 +118,21 @@ var leveldown    = require('leveldown')
           }.bind(this))
         }.bind(this)
 
+        var deferred = {}
+        var self = this
+
+        ;['get', 'put', 'batch', 'del', 'approximateSize']
+          .forEach(function (name) {
+            deferred[name] = function () {
+              var args = [].slice.call(arguments)
+              self.once('ready', function () {
+                self._db[name].apply(self._db, args)
+              })
+            }
+          })
+
+        this._db = deferred
+
         execute()
         this.emit('opening')
       }
@@ -148,18 +163,6 @@ var leveldown    = require('leveldown')
 
       LevelUP.prototype.isClosed = function () { return (/^clos/).test(status) }
 
-      function defer(db, fun) {
-        return function () {
-          if(isOpening()) {
-            var args = [].slice.call(arguments)
-            return db.once('ready', function () {
-              db._db[fun].apply(db._db, args)
-            })
-          }
-          return db._db[fun].apply(db._db, arguments)
-        }
-      }
-
       LevelUP.prototype.get = function (key_, options, callback) {
         var key
           , valueEnc
@@ -177,7 +180,7 @@ var leveldown    = require('leveldown')
         valueEnc = valueEncoding(options)
         options.asBuffer = valueEnc != 'utf8' && valueEnc != 'json'
 
-        defer(this, 'get')(key, options, function (err, value) {
+        this._db.get(key, options, function (err, value) {
           if (err) {
             err = new errors.NotFoundError(
                 'Key not found in database [' + key_ + ']')
@@ -204,7 +207,7 @@ var leveldown    = require('leveldown')
         key     = toSlice[keyEncoding(options)](key_)
         value   = toSlice[valueEncoding(options)](value_)
 
-        defer(this, 'put')(key, value, options, function (err) {
+        this._db.put(key, value, options, function (err) {
           if (err) {
             err = new errors.WriteError(err)
             return dispatchError(err, callback)
@@ -230,7 +233,7 @@ var leveldown    = require('leveldown')
         options = getOptions(options)
         key     = toSlice[keyEncoding(options)](key_)
 
-        defer(this, 'del')(key, options, function (err) {
+        this._db.del(key, options, function (err) {
           if (err) {
             err = new errors.WriteError(err)
             return dispatchError(err, callback)
@@ -280,7 +283,7 @@ var leveldown    = require('leveldown')
           arr = arr_
         }
 
-        defer(this, 'batch')(arr, options, function (err) {
+        this._db.batch(arr, options, function (err) {
           if (err) {
             err = new errors.WriteError(err)
             return dispatchError(err, callback)
@@ -300,7 +303,7 @@ var leveldown    = require('leveldown')
           return dispatchError(err, callback)
         }
 
-        defer(this, 'approximateSize')(start, end, function(err, size) {
+        this._db.approximateSize(start, end, function(err, size) {
           if (err) {
             err = new errors.OpenError(err)
             return dispatchError(err, callback)