datastore: add promise support (#1704)

Author: callmehiphop

README.md

@@ -49,6 +49,19 @@ datastore.save({
     }
   });
 });
+
+// Promises are also supported by omitting callbacks.
+datastore.save({
+  key: blogPostKey,
+  data: blogPostData
+}).then(function() {
+  // The blog post is not published!
+});
+
+// It's also possible to integrate with third-party Promise libraries.
+var datastore = require('@google-cloud/datastore')({
+  promise: require('bluebird')
+});
 ```
 
 

package.json

@@ -50,7 +50,7 @@
     "datastore"
   ],
   "dependencies": {
-    "@google-cloud/common": "^0.6.0",
+    "@google-cloud/common": "^0.7.0",
     "arrify": "^1.0.0",
     "concat-stream": "^1.5.0",
     "create-error-class": "^3.0.2",
@@ -67,6 +67,7 @@
     "deep-strict-equal": "^0.2.0",
     "mocha": "^3.0.1",
     "proxyquire": "^1.7.10",
+    "sinon": "^1.17.6",
     "through2": "^2.0.0"
   },
   "scripts": {

src/query.js

@@ -296,10 +296,40 @@ Query.prototype.offset = function(n) {
  * query.run(function(err, entities, info) {});
  *
  * //-
- * // If you omit the callback, you will get the matching entities in a readable
- * // object stream.
+ * // A keys-only query returns just the keys of the result entities instead of
+ * // the entities themselves, at lower latency and cost.
+ * //-
+ * query.select('__key__');
+ *
+ * query.run(function(err, entities) {
+ *   var keys = entities.map(function(entity) {
+ *     return entity[datastore.KEY];
+ *   });
+ * });
+ *
+ * //-
+ * // If the callback is omitted, we'll return a Promise.
  * //-
- * query.run()
+ * query.run().then(function(data) {
+ *   var entities = data[0];
+ * });
+ */
+Query.prototype.run = function() {
+  var query = this;
+  var args = [query].concat([].slice.call(arguments));
+
+  return this.scope.runQuery.apply(this.scope, args);
+};
+
+/**
+ * Run the query as a readable object stream.
+ *
+ * @param {object=} options - Optional configuration. See
+ *     {module:datastore/query#run} for a complete list of options.
+ * @return {stream}
+ *
+ * @example
+ * query.runStream()
  *   .on('error', console.error)
  *   .on('data', function (entity) {})
  *   .on('info', function(info) {})
@@ -311,28 +341,16 @@ Query.prototype.offset = function(n) {
  * // If you anticipate many results, you can end a stream early to prevent
  * // unnecessary processing and API requests.
  * //-
- * query.run()
- *   .on('data', function(entity) {
+ * query.runStream()
+ *   .on('data', function (entity) {
  *     this.end();
  *   });
- *
- * //-
- * // A keys-only query returns just the keys of the result entities instead of
- * // the entities themselves, at lower latency and cost.
- * //-
- * query.select('__key__');
- *
- * query.run(function(err, entities) {
- *   var keys = entities.map(function(entity) {
- *     return entity[datastore.KEY];
- *   });
- * });
  */
-Query.prototype.run = function() {
+Query.prototype.runStream = function() {
   var query = this;
   var args = [query].concat([].slice.call(arguments));
 
-  return this.scope.runQuery.apply(this.scope, args);
+  return this.scope.runQueryStream.apply(this.scope, args);
 };
 
 module.exports = Query;