Remove step requirement

lib/cartodb/controllers/map.js

@@ -1,6 +1,4 @@
 var _ = require('underscore');
-var assert = require('assert');
-var step = require('step');
 var windshaft = require('windshaft');
 var QueryTables = require('cartodb-query-tables');
 
@@ -346,41 +344,37 @@ MapController.prototype.augmentLayergroupData = function (req, res, callback) {
     callback();
 };
 
-MapController.prototype.getAffectedTables = function (req, res, callback) {
-    const self = this;
+MapController.prototype.getAffectedTables = function (req, res, next) {
     const { dbname, layergroup, user, mapconfig } = res.locals;
 
-    var sql = [];
-    mapconfig.getLayers().forEach(function(layer) {
-        sql.push(layer.options.sql);
-        if (layer.options.affected_tables) {
-            layer.options.affected_tables.map(function(table) {
-                sql.push('SELECT * FROM ' + table + ' LIMIT 0');
-            });
+    this.pgConnection.getConnection(user, (err, connection) => {
+        if (err) {
+            return next(err);
         }
-    });
 
-    step(
-        function getPgConnection() {
-            self.pgConnection.getConnection(user, this);
-        },
-        function getAffectedTablesAndLastUpdatedTime(err, connection) {
-            assert.ifError(err);
-            QueryTables.getAffectedTablesFromQuery(connection, sql.join(';'), this);
-        },
-        function handleAffectedTablesAndLastUpdatedTime(err, affectedTables) {
+        const sql = [];
+        mapconfig.getLayers().forEach(function(layer) {
+            sql.push(layer.options.sql);
+            if (layer.options.affected_tables) {
+                layer.options.affected_tables.map(function(table) {
+                    sql.push('SELECT * FROM ' + table + ' LIMIT 0');
+                });
+            }
+        });
+
+        QueryTables.getAffectedTablesFromQuery(connection, sql.join(';'), (err, affectedTables) => {
             if (err) {
-                return callback(err);
+                return next(err);
             }
 
             // feed affected tables cache so it can be reused from, for instance, layergroup controller
-            self.layergroupAffectedTables.set(dbname, layergroup.layergroupId, affectedTables);
+            this.layergroupAffectedTables.set(dbname, layergroup.layergroupId, affectedTables);
 
             res.locals.affectedTables = affectedTables;
 
-            callback();
-        }
-    );
+            next();
+        });
+    });
 };
 
 MapController.prototype.setCacheChannel = function (req, res, callback) {