use includes instead of indexOf

use _.uniq instead of filter&indexOf

src/controllers/admin/plugins.js

@@ -55,7 +55,7 @@ pluginsController.get = function (req, res, next) {
 					return !plugin.installed;
 				}),
 				incompatible: payload.all.filter(function (plugin) {
-					return compatiblePkgNames.indexOf(plugin.name) === -1;
+					return !compatiblePkgNames.includes(plugin.name);
 				}),
 			});
 		},

src/controllers/admin/settings.js

@@ -36,7 +36,7 @@ function renderEmail(req, res, next) {
 			res.render('admin/settings/email', {
 				emails: results.emails,
 				sendable: results.emails.filter(function (email) {
-					return email.path.indexOf('_plaintext') === -1 && email.path.indexOf('partials') === -1;
+					return !email.path.includes('_plaintext') && !email.path.includes('partials');
 				}),
 				services: results.services,
 			});

src/controllers/admin/uploads.js

@@ -261,7 +261,7 @@ function upload(name, req, res, next) {
 }
 
 function validateUpload(req, res, next, uploadedFile, allowedTypes) {
-	if (allowedTypes.indexOf(uploadedFile.type) === -1) {
+	if (!allowedTypes.includes(uploadedFile.type)) {
 		file.delete(uploadedFile.path);
 		res.json({ error: '[[error:invalid-image-type, ' + allowedTypes.join(', ') + ']]' });
 		return false;