Add limit filter

lib/google-cloud-datastore-database.js

@@ -150,13 +150,15 @@ class GoogleCloudDatastore {
    */
   async all(model, filter, options, callback) {
     const where = filter.where;
+    const limit = filter.limit;
+
     try {
       let result;
 
       if (where && where.id) {
         result = await this.findById(model, where.id);
-      } else if (where) {
-        const query = this.buildQuery(model, where);
+      } else if (where || limit) {
+        const query = this.buildQuery(model, where, limit);
         const entities = await query.run();
 
         result = this.completeEntities(entities[0]);
@@ -175,15 +177,21 @@ class GoogleCloudDatastore {
    * @param {String} model The model name
    * @param {Object} where The filter
    */
-  buildQuery(model, where) {
-    const filters = Object.keys(where).map((key) => ({
-      [key]: where[key],
-    }));
-
+  buildQuery(model, where, limit) {
     let query = this.db.createQuery(model);
 
-    for (let i = 0; i < filters.length; i += 1) {
-      query = this.addFiltersToQuery(query, filters[i]);
+    if (where) {
+      const filters = Object.keys(where).map((key) => ({
+        [key]: where[key],
+      }));
+
+      for (let i = 0; i < filters.length; i += 1) {
+        query = this.addFiltersToQuery(query, filters[i]);
+      }
+    }
+
+    if (limit) {
+      query = query.limit(limit);
     }
 
     return query;

test/model.test.js

@@ -87,6 +87,15 @@ describe('Loopback Google Cloud Datastore Connector', () => {
     });
   });
 
+  it('Should get one entity from all using limit filter', (done) => {
+    Customer.all({limit: 1}, (error, customer) => {
+      customer.should.have.length(1);
+      customer.should.containDeep([{id: customer1.id}]);
+
+      done(error, customer);
+    });
+  });
+
   it('Should find entities by age less than 28', (done) => {
     Customer.find({where: {age: {lt: 28}}}, (error, customer) => {
       customer.should.have.length(2);