Set subdomain to "__unset__" if it empty

This is to prevent invalid network requests with an empty subdomain.

src/js/components/Options.js

@@ -12,7 +12,7 @@ class Options extends Component {
   @observable isSuccess = false;
 
   componentDidMount() {
-    getSettings().then(({ subdomain, apiKey }) => {
+    getSettings(false).then(({ subdomain, apiKey }) => {
       this.subdomain = subdomain || ""
       this.apiKey = apiKey || ""
     })

src/js/utils/browser.js

@@ -1,18 +1,26 @@
+import { head } from "lodash/fp"
 export const isChrome = () => typeof browser === "undefined" && chrome
 export const isFirefox = () => typeof browser !== "undefined" && chrome
-import { head } from "lodash/fp"
 
-export const getSettings = () => {
+export const getSettings = (withDefaultSubdomain = true) => {
   const keys = ["subdomain", "apiKey"]
   const { version } = chrome.runtime.getManifest()
   if (isChrome()) {
     return new Promise(resolve => {
       chrome.storage.sync.get(keys, data => {
+        if (withDefaultSubdomain) {
+          data.subdomain = data.subdomain || "__unset__"
+        }
         resolve({ ...data, version })
       })
     })
   } else {
-    return browser.storage.sync.get(keys).then(data => ({ ...data, version }))
+    return browser.storage.sync.get(keys).then(data => {
+      if (withDefaultSubdomain) {
+        data.subdomain = data.subdomain || "__unset__"
+      }
+      return { ...data, version }
+    })
   }
 }