feat: use native Promise instead of Bluebird, and allow users to switch back.

BREAKING CHANGE:
This change makes all the code that rely on the features provided by Bluebird not working
anymore. For example, `redis.get('foo').timeout(500)` now should be failed since the native
Promise doesn't support the `timeout` method.

You can switch back to the Bluebird implementation by setting `Redis.Promise`:

```
const Redis = require('ioredis')
Redis.Promise = require('bluebird')

const redis = new Redis()

// Use bluebird
assert.equal(redis.get().constructor, require('bluebird'))

// You can change the Promise implementation at any time:
Redis.Promise = global.Promise
assert.equal(redis.get().constructor, global.Promise)
```

Author: luin

README.md

@@ -16,7 +16,7 @@ used in the world's biggest online commerce company [Alibaba](http://www.alibaba
 
 0. Full-featured. It supports [Cluster](http://redis.io/topics/cluster-tutorial), [Sentinel](http://redis.io/topics/sentinel), [Pipelining](http://redis.io/topics/pipelining) and of course [Lua scripting](http://redis.io/commands/eval) & [Pub/Sub](http://redis.io/topics/pubsub) (with the support of binary messages).
 0. High performance.
-0. Delightful API. It works with Node callbacks and [Bluebird promises](https://github.com/petkaantonov/bluebird).
+0. Delightful API. It works with Node callbacks and Native promises.
 0. Transformation of command arguments and replies.
 0. Transparent key prefixing.
 0. Abstraction for Lua scripting, allowing you to define custom commands.
@@ -944,6 +944,24 @@ var redis = new Redis();
 redis.set('foo');
 ```
 
+# Plugging in your own Promises Library
+If you're an advanced user, you may want to plug in your own promise library like [bluebird](https://www.npmjs.com/package/bluebird). Just set Redis.Promise to your favorite ES6-style promise constructor and ioredis will use it.
+
+```javascript
+const Redis = require('ioredis')
+Redis.Promise = require('bluebird')
+
+const redis = new Redis()
+
+// Use bluebird
+assert.equal(redis.get().constructor, require('bluebird'))
+
+// You can change the Promise implementation at any time:
+Redis.Promise = global.Promise
+assert.equal(redis.get().constructor, global.Promise)
+```
+
+
 # Running tests
 
 Start a Redis server on 127.0.0.1:6379, and then:

index.js

@@ -7,6 +7,16 @@ exports.Promise = require('bluebird');
 exports.Cluster = require('./lib/cluster');
 exports.Command = require('./lib/command');
 
+var PromiseContainer = require('./lib/promise_container');
+Object.defineProperty(exports, 'Promise', {
+  get: function() {
+    return PromiseContainer.get();
+  },
+  set: function(lib) {
+    PromiseContainer.set(lib);
+  }
+});
+
 exports.print = function (err, reply) {
   if (err) {
     console.log('Error: ' + err);

lib/cluster/connection_pool.js

@@ -36,7 +36,7 @@ ConnectionPool.prototype.findOrCreate = function (node, readOnly) {
   readOnly = Boolean(readOnly);
 
   if (this.specifiedOptions[node.key]) {
-    _.assign(node, this.specifiedOptions[node.key]);
+    Object.assign(node, this.specifiedOptions[node.key]);
   } else {
     this.specifiedOptions[node.key] = node;
   }

lib/cluster/index.js

@@ -1,6 +1,5 @@
 'use strict';
 
-var Promise = require('bluebird');
 var Deque = require('denque');
 var Redis = require('../redis');
 var utils = require('../utils');
@@ -12,8 +11,10 @@ var ScanStream = require('../scan_stream');
 var Commander = require('../commander');
 var Command = require('../command');
 var commands = require('redis-commands');
+var asCallback = require('standard-as-callback');
 var ConnectionPool = require('./connection_pool');
 var DelayQueue = require('./delay_queue');
+var PromiseContainer = require('../promise_container');
 
 /**
  * Creates a Redis Cluster instance
@@ -112,7 +113,7 @@ Cluster.defaultOptions = {
 };
 
 util.inherits(Cluster, EventEmitter);
-_.assign(Cluster.prototype, Commander.prototype);
+Object.assign(Cluster.prototype, Commander.prototype);
 
 Cluster.prototype.resetOfflineQueue = function () {
   this.offlineQueue = new Deque();
@@ -141,6 +142,7 @@ Cluster.prototype.connect = function () {
     this.resetNodesRefreshInterval();
   }
 
+  var Promise = PromiseContainer.get();
   return new Promise(function (resolve, reject) {
     if (this.status === 'connecting' || this.status === 'connect' || this.status === 'ready') {
       reject(new Error('Redis is already connecting/connected'));
@@ -271,8 +273,10 @@ Cluster.prototype.quit = function (callback) {
     clearInterval(this.slotsTimer);
     this.slotsTimer = null;
   }
+
+  var Promise = PromiseContainer.get();
   if (status === 'wait') {
-    var ret = Promise.resolve('OK').nodeify(callback);
+    var ret = asCallback(Promise.resolve('OK'), callback)
 
     // use setImmediate to make sure "close" event
     // being emitted after quit() is returned
@@ -283,11 +287,14 @@ Cluster.prototype.quit = function (callback) {
 
     return ret;
   }
-  return Promise.all(this.nodes().map(function (node) {
-    return node.quit();
-  })).then(function () {
-    return 'OK';
-  }).nodeify(callback);
+  return asCallback(
+    Promise.all(this.nodes().map(function (node) {
+      return node.quit();
+    })).then(function () {
+      return 'OK';
+    }),
+    callback
+  );
 };
 
 /**

lib/command.js

@@ -1,11 +1,12 @@
 'use strict';
 
 var _ = require('./utils/lodash');
-var Promise = require('bluebird');
 var fbuffer = require('flexbuffer');
 var utils = require('./utils');
 var commands = require('redis-commands');
 var calculateSlot = require('cluster-key-slot');
+var PromiseContainer = require('./promise_container');
+var asCallback = require('standard-as-callback');
 
 /**
  * Command instance
@@ -60,7 +61,8 @@ function Command(name, args, options, callback) {
 
 Command.prototype.initPromise = function () {
   var _this = this;
-  this.promise = new Promise(function (resolve, reject) {
+  var Promise = PromiseContainer.get();
+  var promise = new Promise(function (resolve, reject) {
     if (!_this.transformed) {
       _this.transformed = true;
       var transformer = Command._transformer.argument[_this.name];
@@ -78,7 +80,9 @@ Command.prototype.initPromise = function () {
     } else {
       _this.reject = reject;
     }
-  }).nodeify(this.callback);
+  });
+
+  this.promise = asCallback(promise, this.callback);
 };
 
 Command.prototype.getSlot = function () {

lib/commander.js

@@ -3,7 +3,8 @@
 var _ = require('./utils/lodash');
 var Command = require('./command');
 var Script = require('./script');
-var Promise = require('bluebird');
+var PromiseContainer = require('./promise_container');
+var asCallback = require('standard-as-callback');
 
 var DROP_BUFFER_SUPPORT_ERROR = '*Buffer methods are not available ' +
   'because "dropBufferSupport" option is enabled.' +
@@ -114,7 +115,10 @@ function generateFunction(_commandName, _encoding) {
     var options;
     if (this.options.dropBufferSupport) {
       if (!_encoding) {
-        return Promise.reject(new Error(DROP_BUFFER_SUPPORT_ERROR)).nodeify(callback);
+        return asCallback(
+          PromiseContainer.get().reject(new Error(DROP_BUFFER_SUPPORT_ERROR)),
+          callback
+        )
       }
       options = { replyEncoding: null };
     } else {
@@ -150,7 +154,10 @@ function generateScriptingFunction(_script, _encoding) {
     var options;
     if (this.options.dropBufferSupport) {
       if (!_encoding) {
-        return Promise.reject(new Error(DROP_BUFFER_SUPPORT_ERROR)).nodeify(callback);
+        return asCallback(
+          PromiseContainer.get().reject(new Error(DROP_BUFFER_SUPPORT_ERROR)),
+          callback
+        )
       }
       options = { replyEncoding: null };
     } else {

lib/connectors/connector.js

@@ -29,7 +29,7 @@ Connector.prototype.connect = function (callback) {
     connectionOptions = _.pick(this.options, ['port', 'host', 'family']);
   }
   if (this.options.tls) {
-    _.assign(connectionOptions, this.options.tls);
+    Object.assign(connectionOptions, this.options.tls);
   }
 
   var _this = this;

lib/pipeline.js

@@ -3,10 +3,11 @@ var _ = require('./utils/lodash');
 var Commander = require('./commander');
 var Command = require('./command');
 var fbuffer = require('flexbuffer');
-var Promise = require('bluebird');
 var util = require('util');
+var asCallback = require('standard-as-callback');
 var commands = require('redis-commands');
 var calculateSlot = require('cluster-key-slot');
+var PromiseContainer = require('./promise_container');
 
 function Pipeline(redis) {
   Commander.call(this);
@@ -20,13 +21,14 @@ function Pipeline(redis) {
   this._shaToScript = {};
 
   var _this = this;
-  _.keys(redis.scriptsSet).forEach(function (name) {
+  Object.keys(redis.scriptsSet).forEach(function (name) {
     var script = redis.scriptsSet[name];
     _this._shaToScript[script.sha] = script;
     _this[name] = redis[name];
     _this[name + 'Buffer'] = redis[name + 'Buffer'];
   });
 
+  var Promise = PromiseContainer.get()
   this.promise = new Promise(function (resolve, reject) {
     _this.resolve = resolve;
     _this.reject = reject;
@@ -39,7 +41,7 @@ function Pipeline(redis) {
   });
 }
 
-_.assign(Pipeline.prototype, Commander.prototype);
+Object.assign(Pipeline.prototype, Commander.prototype);
 
 Pipeline.prototype.fillResult = function (value, position) {
   var i;
@@ -213,7 +215,7 @@ Pipeline.prototype.exec = function (callback) {
   }
   if (!this.nodeifiedPromise) {
     this.nodeifiedPromise = true;
-    this.promise.nodeify(callback);
+    asCallback(this.promise, callback);
   }
   if (_.isEmpty(this._queue)) {
     this.resolve([]);
@@ -273,6 +275,7 @@ Pipeline.prototype.exec = function (callback) {
         pending.push(scripts[i]);
       }
     }
+    var Promise = PromiseContainer.get()
     return Promise.all(pending.map(function (script) {
       return _this.redis.script('load', script.lua);
     }));

lib/promise_container.js

@@ -0,0 +1,19 @@
+exports.isPromise = function (obj) {
+  return !!obj &&
+    (typeof obj === 'object' || typeof obj === 'function') &&
+    typeof obj.then === 'function'
+}
+
+let promise = global.Promise
+
+exports.get = function () {
+  return promise
+}
+
+exports.set = function (lib) {
+  if (typeof lib !== 'function') {
+    throw new Error(`Provided Promise must be a function, got ${lib}`)
+  }
+
+  promise = lib
+}

lib/redis.js

@@ -3,17 +3,18 @@
 var _ = require('./utils/lodash');
 var util = require('util');
 var EventEmitter = require('events').EventEmitter;
-var Promise = require('bluebird');
 var Deque = require('denque');
 var Command = require('./command');
 var Commander = require('./commander');
 var utils = require('./utils');
+var asCallback = require('standard-as-callback');
 var eventHandler = require('./redis/event_handler');
 var debug = require('./utils/debug')('ioredis:redis');
 var Connector = require('./connectors/connector');
 var SentinelConnector = require('./connectors/sentinel_connector');
 var ScanStream = require('./scan_stream');
 var commands = require('redis-commands');
+var PromiseContainer = require('./promise_container');
 
 /**
  * Creates a Redis instance
@@ -131,7 +132,7 @@ function Redis() {
 }
 
 util.inherits(Redis, EventEmitter);
-_.assign(Redis.prototype, Commander.prototype);
+Object.assign(Redis.prototype, Commander.prototype);
 
 /**
  * Create a Redis instance
@@ -248,7 +249,8 @@ Redis.prototype.setStatus = function (status, arg) {
  * @public
  */
 Redis.prototype.connect = function (callback) {
-  return new Promise(function (resolve, reject) {
+  var Promise = PromiseContainer.get();
+  var promise = new Promise(function (resolve, reject) {
     if (this.status === 'connecting' || this.status === 'connect' || this.status === 'ready') {
       reject(new Error('Redis is already connecting/connected'));
       return;
@@ -315,7 +317,9 @@ Redis.prototype.connect = function (callback) {
     }, function (type, err) {
       _this.silentEmit(type, err);
     });
-  }.bind(this)).nodeify(callback);
+  }.bind(this))
+
+  return asCallback(promise, callback)
 };
 
 /**
@@ -362,7 +366,7 @@ Redis.prototype.end = function () {
  * @public
  */
 Redis.prototype.duplicate = function (override) {
-  return new Redis(_.assign(_.cloneDeep(this.options), override || {}));
+  return new Redis(Object.assign(_.cloneDeep(this.options), override || {}));
 };
 
 /**
@@ -511,11 +515,15 @@ Redis.prototype.monitor = function (callback) {
     lazyConnect: false
   });
 
-  return new Promise(function (resolve) {
-    monitorInstance.once('monitoring', function () {
-      resolve(monitorInstance);
-    });
-  }).nodeify(callback);
+  var Promise = PromiseContainer.get();
+  return asCallback(
+    new Promise(function (resolve) {
+      monitorInstance.once('monitoring', function () {
+        resolve(monitorInstance);
+      });
+    }),
+    callback
+  );
 };
 
 require('./transaction').addTransactionSupport(Redis.prototype);
@@ -636,6 +644,6 @@ Redis.prototype.sendCommand = function (command, stream) {
   };
 });
 
-_.assign(Redis.prototype, require('./redis/parser'));
+Object.assign(Redis.prototype, require('./redis/parser'));
 
 module.exports = Redis;