viacep: browser user-agent error

Author: Ivan Correa

src/services/viacep.js

@@ -9,11 +9,14 @@ export default function fetchViaCepService (cepWithLeftPad, proxyURL = '') {
     method: 'GET',
     mode: 'cors',
     headers: {
-      'content-type': 'application/json;charset=utf-8',
-      'user-agent': ''
+      'content-type': 'application/json;charset=utf-8'
     }
   }
 
+  if (typeof window == 'undefined') {
+    options.headers['user-agent'] = 'cep-promise'
+  }
+
   return fetch(url, options)
     .then(analyzeAndParseResponse)
     .then(checkForViaCepError)