Refactor promisify() code by using catering module

Author: Lars-Magnus Skog

lib/batch.js

@@ -1,5 +1,5 @@
 var WriteError = require('level-errors').WriteError
-var promisify = require('./promisify')
+var catering = require('catering')
 var getCallback = require('./common').getCallback
 var getOptions = require('./common').getOptions
 
@@ -53,15 +53,9 @@ Batch.prototype.clear = function () {
 Batch.prototype.write = function (options, callback) {
   var levelup = this._levelup
   var ops = this.ops
-  var promise
 
   callback = getCallback(options, callback)
-
-  if (!callback) {
-    callback = promisify()
-    promise = callback.promise
-  }
-
+  callback = catering.fromCallback(callback)
   options = getOptions(options)
 
   try {
@@ -74,7 +68,7 @@ Batch.prototype.write = function (options, callback) {
     throw new WriteError(err)
   }
 
-  return promise
+  return callback.promise
 }
 
 module.exports = Batch

lib/levelup.js

@@ -7,7 +7,7 @@ var Batch = require('./batch')
 var errors = require('level-errors')
 var supports = require('level-supports')
 var assert = require('assert')
-var promisify = require('./promisify')
+var catering = require('catering')
 var getCallback = require('./common').getCallback
 var getOptions = require('./common').getOptions
 
@@ -86,30 +86,26 @@ inherits(LevelUP, EventEmitter)
 
 LevelUP.prototype.open = function (opts, callback) {
   var self = this
-  var promise
 
   if (typeof opts === 'function') {
     callback = opts
     opts = null
   }
 
-  if (!callback) {
-    callback = promisify()
-    promise = callback.promise
-  }
+  callback = catering.fromCallback(callback)
 
   if (!opts) {
     opts = this.options
   }
 
   if (this.isOpen()) {
     process.nextTick(callback, null, self)
-    return promise
+    return callback.promise
   }
 
   if (this._isOpening()) {
     this.once('open', function () { callback(null, self) })
-    return promise
+    return callback.promise
   }
 
   this.emit('opening')
@@ -124,17 +120,13 @@ LevelUP.prototype.open = function (opts, callback) {
     self.emit('ready')
   })
 
-  return promise
+  return callback.promise
 }
 
 LevelUP.prototype.close = function (callback) {
   var self = this
-  var promise
 
-  if (!callback) {
-    callback = promisify()
-    promise = callback.promise
-  }
+  callback = catering.fromCallback(callback)
 
   if (this.isOpen()) {
     this.db.close(function () {
@@ -153,7 +145,7 @@ LevelUP.prototype.close = function (callback) {
     })
   }
 
-  return promise
+  return callback.promise
 }
 
 LevelUP.prototype.isOpen = function () {
@@ -169,17 +161,13 @@ LevelUP.prototype.isClosed = function () {
 }
 
 LevelUP.prototype.get = function (key, options, callback) {
-  var promise
-
   callback = getCallback(options, callback)
+  callback = catering.fromCallback(callback)
 
-  if (!callback) {
-    callback = promisify()
-    promise = callback.promise
+  if (maybeError(this, callback)) {
+    return callback.promise
   }
 
-  if (maybeError(this, callback)) { return promise }
-
   options = getOptions(options)
 
   this.db.get(key, options, function (err, value) {
@@ -194,22 +182,19 @@ LevelUP.prototype.get = function (key, options, callback) {
     callback(null, value)
   })
 
-  return promise
+  return callback.promise
 }
 
 LevelUP.prototype.put = function (key, value, options, callback) {
   var self = this
-  var promise
 
   callback = getCallback(options, callback)
+  callback = catering.fromCallback(callback)
 
-  if (!callback) {
-    callback = promisify()
-    promise = callback.promise
+  if (maybeError(this, callback)) {
+    return callback.promise
   }
 
-  if (maybeError(this, callback)) { return promise }
-
   options = getOptions(options)
 
   this.db.put(key, value, options, function (err) {
@@ -220,22 +205,19 @@ LevelUP.prototype.put = function (key, value, options, callback) {
     callback()
   })
 
-  return promise
+  return callback.promise
 }
 
 LevelUP.prototype.del = function (key, options, callback) {
   var self = this
-  var promise
 
   callback = getCallback(options, callback)
+  callback = catering.fromCallback(callback)
 
-  if (!callback) {
-    callback = promisify()
-    promise = callback.promise
+  if (maybeError(this, callback)) {
+    return callback.promise
   }
 
-  if (maybeError(this, callback)) { return promise }
-
   options = getOptions(options)
 
   this.db.del(key, options, function (err) {
@@ -246,7 +228,7 @@ LevelUP.prototype.del = function (key, options, callback) {
     callback()
   })
 
-  return promise
+  return callback.promise
 }
 
 LevelUP.prototype.batch = function (arr, options, callback) {
@@ -255,17 +237,15 @@ LevelUP.prototype.batch = function (arr, options, callback) {
   }
 
   var self = this
-  var promise
 
   if (typeof arr === 'function') callback = arr
   else callback = getCallback(options, callback)
 
-  if (!callback) {
-    callback = promisify()
-    promise = callback.promise
-  }
+  callback = catering.fromCallback(callback)
 
-  if (maybeError(this, callback)) { return promise }
+  if (maybeError(this, callback)) {
+    return callback.promise
+  }
 
   options = getOptions(options)
 
@@ -277,7 +257,7 @@ LevelUP.prototype.batch = function (arr, options, callback) {
     callback()
   })
 
-  return promise
+  return callback.promise
 }
 
 LevelUP.prototype.iterator = function (options) {
@@ -286,18 +266,13 @@ LevelUP.prototype.iterator = function (options) {
 
 LevelUP.prototype.clear = function (options, callback) {
   var self = this
-  var promise
 
   callback = getCallback(options, callback)
   options = getOptions(options)
-
-  if (!callback) {
-    callback = promisify()
-    promise = callback.promise
-  }
+  callback = catering.fromCallback(callback)
 
   if (maybeError(this, callback)) {
-    return promise
+    return callback.promise
   }
 
   this.db.clear(options, function (err) {
@@ -308,7 +283,7 @@ LevelUP.prototype.clear = function (options, callback) {
     callback()
   })
 
-  return promise
+  return callback.promise
 }
 
 LevelUP.prototype.readStream =

lib/promisify.js

@@ -14,6 +14,7 @@
     "prepublishOnly": "npm run dependency-check"
   },
   "dependencies": {
+    "catering": "~2.0.0",
     "deferred-leveldown": "~5.3.0",
     "level-errors": "~2.0.0",
     "level-iterator-stream": "~4.0.0",