Added example with eventual read consistency in Node.js (#480)

Author: irri

samples/README.md

@@ -47,7 +47,8 @@ Commands:
   delete <taskId>    Deletes a task.
 
 Options:
-  --help  Show help                                                                                            [boolean]
+  --version  Show version number                                                                               [boolean]
+  --help     Show help                                                                                         [boolean]
 
 Examples:
   node tasks.js new "Buy milk"  Adds a task with description "Buy milk".

samples/concepts.js

@@ -1033,9 +1033,25 @@ class Query extends TestHelper {
 
   testEventualConsistentQuery (t) {
     t.plan(0);
+    const datastoreMock = datastore;
+    datastore = this.datastore;
     // [START eventual_consistent_query]
-    // Read consistency cannot be specified in google-cloud-node.
+    const ancestorKey = datastore.key(['TaskList', 'default']);
+    const query = datastore.createQuery('Task')
+      .hasAncestor(ancestorKey);
+
+    query.run({ consistency: 'eventual' });
     // [END eventual_consistent_query]
+    return query.run({ consistency: 'eventual' })
+      .then((results) => {
+        datastore = datastoreMock;
+        const entities = results[0];
+        return entities;
+      })
+      .catch((err) => {
+        datastore = datastoreMock;
+        return Promise.reject(err);
+      });
   }
 }
 

samples/package.json

@@ -9,7 +9,7 @@
     "url": "https://github.com/GoogleCloudPlatform/nodejs-docs-samples.git"
   },
   "engines": {
-    "node": ">=4.3.2"
+    "node": ">=4"
   },
   "scripts": {
     "lint": "samples lint",
@@ -18,13 +18,13 @@
   },
   "dependencies": {
     "@google-cloud/datastore": "1.1.0",
-    "yargs": "8.0.2"
+    "yargs": "9.0.1"
   },
   "devDependencies": {
     "@google-cloud/nodejs-repo-tools": "1.4.17",
-    "ava": "0.21.0",
+    "ava": "0.22.0",
     "proxyquire": "1.8.0",
-    "sinon": "3.2.0"
+    "sinon": "3.3.0"
   },
   "cloud-repo-tools": {
     "requiresKeyFile": true,