server/models/response.js
var helper = require('./models-helper');
Response = function() {
var startTime = new Date().getTime();
this.meta = {};
this.data = {};
this.calculateExecutionTime = function () {
var endTime = new Date().getTime();
this.meta.execution_time = String ((endTime - startTime) / 1000) + 's' ;
}
}