add support for model parameter

packages/translate/src/index.js

@@ -312,6 +312,9 @@ Translate.prototype.getLanguages = function(target, callback) {
  *     is written in.
  * @param {string} options.to - The ISO 639-1 language code to translate the
  *     input to.
+ * @param {string} options.model - **Note:** Users must be whitelisted to use
+ *     this parameter. You can use this parameter to take advantage of Neural
+ *     Machine Translation. Possible values are 'base' and 'nmt'.
  * @param {function} callback - The callback function.
  * @param {?error} callback.err - An error returned while making this request.
  * @param {object|object[]} callback.translations - If a single string input was
@@ -388,6 +391,10 @@ Translate.prototype.translate = function(input, options, callback) {
     if (options.to) {
       query.target = options.to;
     }
+
+    if (options.model) {
+      query.model = options.model;
+    }
   }
 
   if (!query.target) {

packages/translate/test/index.js

@@ -406,6 +406,22 @@ describe('Translate', function() {
       });
     });
 
+    describe('options.model', function() {
+      it('should set the model option when available', function(done) {
+        var fakeOptions = {
+          model: 'nmt',
+          to: 'es'
+        };
+
+        translate.request = function(reqOpts) {
+          assert.strictEqual(reqOpts.json.model, 'nmt');
+          done();
+        };
+
+        translate.translate(INPUT, fakeOptions, assert.ifError);
+      });
+    });
+
     it('should make the correct API request', function(done) {
       translate.request = function(reqOpts) {
         assert.strictEqual(reqOpts.uri, '');