refactor: use string interpolation

Author: dpopp07

speech-to-text/get-models.js

@@ -54,9 +54,9 @@ module.exports = function getModels(options) {
   };
   var url = options.url || 'https://stream.watsonplatform.net/speech-to-text/api';
   if (options.access_token) {
-    url = url + '/v1/models?access_token=' + options.access_token;
+    url = `${url}/v1/models?access_token=${options.access_token}`;
   } else {
-    url = url + '/v1/models?watson-token=' + options.token;
+    url = `${url}/v1/models?access_token=${options.token}`;
   }
   return fetch(url, reqOpts)
     .then(function(response) {

text-to-speech/get-voices.js

@@ -55,9 +55,9 @@ module.exports = function getVoices(options) {
   };
   var url = options.url || 'https://stream.watsonplatform.net/text-to-speech/api';
   if (options.access_token) {
-    url = url + '/v1/voices?watson-token=' + options.access_token;
+    url = `${url}'/v1/voices?watson-token='${options.access_token}`;
   } else {
-    url = url + '/v1/voices?watson-token=' + options.token;
+    url = `${url}'/v1/voices?watson-token='${options.token}`;
   }
   return fetch(url, reqOpts)
     .then(function(response) {

text-to-speech/synthesize.js

@@ -51,7 +51,7 @@ module.exports = function synthesize(options) {
   var url = options.url || 'https://stream.watsonplatform.net/text-to-speech/api';
   var audio = options.element || new Audio();
   audio.crossOrigin = 'anonymous';
-  audio.src = url + '/v1/synthesize?' + qs.stringify(pick(options, QUERY_PARAMS_ALLOWED));
+  audio.src = `${url}/v1/synthesize?${qs.stringify(pick(options, QUERY_PARAMS_ALLOWED))}`;
   if (options.autoPlay !== false) {
     audio.play();
   }