Fix eslint errors and add npm script for eslint (#5427)

* re-enable auth check for device status routes

* Resolve eslint errors

* Add npm script for eslint

* Correct regex for express extension middleware and add tests for expected behaviour

* Resolve lint error in virtual assistant base

* Update index.js

* Update index.js

tests/expressextensions.test.js

@@ -0,0 +1,33 @@
+'use strict';
+
+require('should');
+
+var extensionsMiddleware = require('../lib/middleware/express-extension-to-accept.js');
+
+var acceptJsonRequests = extensionsMiddleware(['json']);
+
+describe('Express extension middleware', function ( ) {
+
+  it('Valid json request should be given accept header for application/json', function () {
+    var entriesRequest = {
+      path: '/api/v1/entries.json',
+      url: '/api/v1/entries.json',
+      headers: {}
+    };
+
+    acceptJsonRequests(entriesRequest, {}, () => {});
+    entriesRequest.headers.accept.should.equal('application/json');
+  });
+
+  it('Invalid json request should NOT be given accept header', function () {
+    var invalidEntriesRequest = {
+      path: '/api/v1/entriesXjson',
+      url: '/api/v1/entriesXjson',
+      headers: {}
+    };
+
+    acceptJsonRequests(invalidEntriesRequest, {}, () => {});
+    should(invalidEntriesRequest.headers.accept).not.be.ok;
+  });
+
+});