A worflow oriented controller

workflow-oriented-controller.js

// No middleware, just pur functions
import getBodyFromReq from 'pureBodyParser';
import getQueryFromReq from 'pureQueryParser';
import sendToRes from 'pureResponseMaker';

// Use dependency injection for required services
// app/config/timer just come from this function caller
module.exports = ({ app, config, timer}) => {
  
  app.post((req, res) => {
    // Promise based workflow instead of a middleware chain
    // could have been async/await too
    Promise.all([
      // No surprise, the body comes from the pureBodyParser module
      // But i can already guess it allows JSON or YAML
      getBodyFromReq.bind(null, req, ['json', 'yaml']),
      // And so on for the query
      getQueryFromReq.bind(null, req),
    ])
    .then(_buildResponse.bind(null, {timer, config})
    // No surprise, the response is sent by the pureResponseMaker module
    // But i can already guess it could output JSON or YAML
    .sendToRes(sendToRes.bind(null, req, res, ['json', 'yaml'], 200));
  });

};

// the pure function that process the request
// could be reused in a completly different context
// a frontend service worker or a websocket server
function _buildResponse({timer, config}, [body, query]) => {
    const data = {};
    if(query.ms) {
      data.when = timer.now();
    } else {
      data.when = new Date(timer.now()).toISOString();
    }
    if(config.repeatBody) {
      data.body = req.body;
    }
    return data;
  }