fix: only register properly configured sync services

README.md

@@ -3,7 +3,6 @@
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@@ -18,18 +17,11 @@ Join our Discord server:
 
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-## Environment Variables
-
-The following environment variables will be injected at compilation time for some features to work:
-
-- `SYNC_GOOGLE_CLIENT_ID` / `SYNC_GOOGLE_CLIENT_SECRET` - Google sync service
-- `SYNC_ONEDRIVE_CLIENT_ID` / `SYNC_ONEDRIVE_CLIENT_SECRET` - OneDrive sync service
-
 ## Workflows
 
 ### Development
 
-Install [Node.js](https://nodejs.org/) and Yarn v1.x.  
+Install [Node.js](https://nodejs.org/) and Yarn v1.x.
 The version of Node.js should match `"node"` key in `package.json`.
 
 ``` sh

src/background/sync/dropbox.js

@@ -174,7 +174,7 @@ const Dropbox = BaseService.extend({
     return this.prepare();
   },
 });
-register(Dropbox);
+if (config.client_id) register(Dropbox);
 
 function normalize(item) {
   return {

src/background/sync/googledrive.js

@@ -217,7 +217,7 @@ const GoogleDrive = BaseService.extend({
     });
   },
 });
-register(GoogleDrive);
+if (config.client_id && config.client_secret) register(GoogleDrive);
 
 function normalize(item) {
   return {

src/background/sync/onedrive.js

@@ -156,7 +156,7 @@ const OneDrive = BaseService.extend({
     });
   },
 });
-register(OneDrive);
+if (config.client_id && config.client_secret) register(OneDrive);
 
 function normalize(item) {
   return {