Follow middleware pattern, return a function as the actual middleware

lib/cartodb/controllers/named_maps_admin.js

@@ -24,7 +24,7 @@ NamedMapsAdminController.prototype.register = function (app) {
         `${base_url_templated}/`,
         cors(),
         userMiddleware(),
-        localsMiddleware,
+        localsMiddleware(),
         credentialsMiddleware(),
         this.checkContentType('POST', 'POST TEMPLATE'),
         this.authorizedByAPIKey('create', 'POST TEMPLATE'),
@@ -35,7 +35,7 @@ NamedMapsAdminController.prototype.register = function (app) {
         `${base_url_templated}/:template_id`,
         cors(),
         userMiddleware(),
-        localsMiddleware,
+        localsMiddleware(),
         credentialsMiddleware(),
         this.checkContentType('PUT', 'PUT TEMPLATE'),
         this.authorizedByAPIKey('update', 'PUT TEMPLATE'),
@@ -46,7 +46,7 @@ NamedMapsAdminController.prototype.register = function (app) {
         `${base_url_templated}/:template_id`,
         cors(),
         userMiddleware(),
-        localsMiddleware,
+        localsMiddleware(),
         credentialsMiddleware(),
         this.authorizedByAPIKey('get', 'GET TEMPLATE'),
         this.retrieve()
@@ -56,7 +56,7 @@ NamedMapsAdminController.prototype.register = function (app) {
         `${base_url_templated}/:template_id`,
         cors(),
         userMiddleware(),
-        localsMiddleware,
+        localsMiddleware(),
         credentialsMiddleware(),
         this.authorizedByAPIKey('delete', 'DELETE TEMPLATE'),
         this.destroy()
@@ -66,7 +66,7 @@ NamedMapsAdminController.prototype.register = function (app) {
         `${base_url_templated}/`,
         cors(),
         userMiddleware(),
-        localsMiddleware,
+        localsMiddleware(),
         credentialsMiddleware(),
         this.authorizedByAPIKey('list', 'GET TEMPLATE LIST'),
         this.list()

lib/cartodb/middleware/context/index.js

@@ -7,7 +7,7 @@ const dbConnSetup = require('./db-conn-setup');
 
 module.exports = function prepareContextMiddleware(authApi, pgConnection) {
     return [
-        locals,
+        locals(),
         cleanUpQueryParams(),
         layergroupToken,
         credentials(),

lib/cartodb/middleware/context/locals.js

@@ -1,6 +1,7 @@
-module.exports = function localsMiddleware(req, res, next) {
-    // save req.params in res.locals
-    res.locals = Object.assign(req.params || {}, res.locals);
+module.exports = function locals () {
+    return function localsMiddleware (req, res, next) {
+        res.locals = Object.assign(req.params || {}, res.locals);
 
-    next();
+        next();
+    };
 };

test/unit/cartodb/prepare-context.test.js

@@ -65,10 +65,11 @@ describe('prepare-context', function() {
     }
 
     it('res.locals are created', function(done) {
+        const locals = localsMiddleware();
         let req = {};
         let res = {};
 
-        localsMiddleware(prepareRequest(req), prepareResponse(res), function(err) {
+        locals(prepareRequest(req), prepareResponse(res), function(err) {
             if ( err ) { done(err); return; }
             assert.ok(res.hasOwnProperty('locals'), 'response has locals');
             done();