Aspect Oriented Programming with FeathersJS 

Why Aspect? 

Why Aspect ... var express = require('express'); var app = express(); app.update('/', function (req, res, next) { if (isLoggedln(req) && isValidate(req)) { getUser(req.params.userId).then(function (user) { if (isAdmin(user) && isCurrent(user)) { updateInfo(req).then(function (info) { if (info.emailme) { sendEmail(user.email, info) } removePassword(user); res.send(info); }) } }); } }); because systems grow 

@abraao4lves Software Engennier abraaoalves.github.io 

Inspiration: Functional Programming f(g(x)) 

Continuation–passing style (CPS) 

Continuation–passing style (CPS) let createUser = validateRequest >> verifyEmail >> db.createUser >> smtpServer.sendEmail >> returnMessage F# Example: 

(CPS) with NodeJS ? 

var express = require('express'); var bodyParser = require('body-parser'); var app = express(); app .use(bodyParser.json()) .use(function (req, res, next) { getUser(req.params.userId).then(function(user){ req.body.username = user.name; next() }) }) .use(function (req, res) { res.json(req.body || {message:'No content'}) }) (CPS) with NodeJS! Express - Middlewares 

var express = require('express'); var bodyParser = require('body-parser'); var app = express(); app .use(bodyParser.json()) .use(function (req, res, next) { getUser(req.params.userId).then(function(user){ req.body.username = user.name; next() }) }) .use(function (req, res) { res.json(req.body || {message:'No content'}) }) (CPS) with NodeJS! Express - Middlewares 

And ... Aspect Oriented Programming? 

Aspect Oriented Programming! 

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Get Starter 

(CPS) with FeathersJS 

(CPS) with FeathersJS // Register the hooks app.service('users') .before({ find: [isLoggedIn, isAdmin], get: [isLoggedIn, isCurrent], create: hashPassword }) .after(removePasswords) .after({ create: sendEmail }); 

(CPS) with FeathersJS // Register the hooks app.service('users') .before({ find: [isLoggedIn, isAdmin], get: [isLoggedIn, isCurrent], create: hashPassword }) .after(removePasswords) .after({ create: sendEmail }); 

(CPS) with FeathersJS // Register the hooks app.service('users') .before({ find: [isLoggedIn, isAdmin], get: [isLoggedIn, isCurrent], create: hashPassword }) // To all methods .after(removePasswords) .after({ create: sendEmail }); 

DEMO 

Thanks. @abraao4lves abraaoalves.github.io