Fix lint error & add lint phase in travis CI

.travis.yml

@@ -1,3 +1,7 @@
 language: node_js
 node_js:
   - "lts/*" # Use LTS version
+
+script:
+  - npm run lint
+  - npm test

src/common/workerUtils.js

@@ -225,7 +225,7 @@ const handleRecognize = ({
             TessModule._free(ptr);
             res.resolve({ files, ...result });
           } catch (err) {
-            res.reject({ err: err });
+            res.reject({ err });
           }
         })
     ))