Add async iterator interface to cursors

lib/cursor.js

@@ -2,6 +2,7 @@ var Promise = require('bluebird');
 var Err = require(__dirname+'/error.js');
 var helper = require(__dirname+'/helper.js');
 var EventEmitter = require('events').EventEmitter;
+var $$asyncIterator = require('iterall').$$asyncIterator;
 
 var MAX_CALL_STACK = 1000;
 
@@ -366,6 +367,37 @@ Cursor.prototype._eachCb = function(err, data) {
   }
 }
 
+Cursor.prototype.asyncIterator = function() {
+  var self = this;
+  return {
+    next: function() {
+      var iter = this;
+      return self._next().then(value => {
+        return {
+          done: false,
+          value: value
+        };
+      }).error(function(error) {
+        if ((error.message !== 'You cannot retrieve data from a cursor that is closed.') &&
+            (error.message.match(/You cannot call `next` on a closed/) === null)) {
+          return iter.throw(error);
+        } else {
+          return iter.return();
+        }
+      });
+    },
+    return: function() {
+      return Promise.resolve({ value: undefined, done: true });
+    },
+    throw: function(err) {
+      return Promise.reject(err);
+    },
+    [$$asyncIterator]: function() {
+      return this;
+    }
+
+}}
+
 var methods = [
   'addListener',
   'on',

package.json

@@ -26,7 +26,8 @@
     "url": "https://github.com/neumino/rethinkdbdash/issues"
   },
   "dependencies": {
-    "bluebird": ">= 3.0.1"
+    "bluebird": ">= 3.0.1",
+    "iterall": "^1.2.2"
   },
   "devDependencies": {
     "mocha": ">= 1.20.0",

test/cursor.js

@@ -2,6 +2,7 @@ var config = require('./config.js');
 var r = require('../lib')(config);
 var util = require(__dirname+'/util/common.js');
 var assert = require('assert');
+var iterall = require('iterall');
 
 var uuid = util.uuid;
 var It = util.It
@@ -841,5 +842,35 @@ It('`eachAync` should return an error if the connection dies', function* (done)
   // Kill the TCP connection
   connection.connection.end()
 })
+It('`asyncIterator` should return an async iterator', function* (done) {
+  try {
+    var connection = yield r.connect({host: config.host, port: config.port, authKey: config.authKey});
+    assert(connection);
 
-
+    var feed = yield r.db(dbName).table(tableName).changes().run(connection);
+    var iterator = feed.asyncIterator();
+    assert(iterall.isAsyncIterable(iterator))
+    connection.connection.end()
+    done();
+  } catch(err) {
+    done(err);
+  }
+})
+It('`asyncIterator` should have a working `next`method', function* (done) {
+  try {
+    feed = yield r.db(dbName).table(tableName2).changes().run();
+    var value = 1;
+    setTimeout(function() {
+      r.db(dbName).table(tableName2).update({foo: value}).run();
+    }, 100)
+    assert(feed);
+    var iterator = feed.asyncIterator();
+    assert(iterator);
+    var i=0;
+    var result = yield iterator.next();
+    assert(result.value.new_val.foo === value);
+    done();
+  } catch(err) {
+    done(err);
+  }
+})