text: 'use strict';
  
  const jayson = require('jayson/promise');
  const _ = require('lodash');
  
  const server = new jayson.server({
  
    add: function(args) {
      return new Promise(function(resolve, reject) {
        const sum = _.reduce(args, function(sum, value) { return sum + value; }, 0);
        resolve(sum);
      });
    }
  
  });
  
  server.http().listen(3000);
  