Stefan Pante@stefanpante

Node.js at Digipolis: Experiences and lessons learned24/03/2016

The Node.js Team

A-stad

Stack

A-profiel (user app)

meldingene-loket notificati

on redactie ... helpcenter

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n

Civilian/Employee

Centrale Reference Systems

A-profiel (user app)

meldingene-loket notificati

on redactie ... helpcenter

cart(betalen) search stadspla

n

Civilian/Employee

Good Ideas1. Reusable modules

Good Ideas1. Reusable modules

2. Basic application structure

Good Ideas1. Reusable modules

2. Basic application structure

3. Code Quality

1. Reusable modules

New Application

User Service

Apache Solr

Notification Service

Modules● Communication and Authorization

Modules● Communication and Authorization

● Common tasks: mailing, response handling…

Modules● Communication and Authorization

● Common tasks: mailing, response handling…

● Wrapper around existing modules, with specific

configuration

Astad module was born

All dependencies you’d ever need

Everything initialised and exposed on Express app

Disadvantages● Hard to maintain (versioning difficult)

Disadvantages● Hard to maintain (versioning difficult)

● Many unused dependencies

Disadvantages● Hard to maintain (versioning difficult)

● Many unused dependencies

● Scripts, cron jobs…

Disadvantages● Hard to maintain (versioning difficult)

● Many unused dependencies

● Scripts, cron jobs…

● Required intrinsic knowledge

Astad Module

Astad Module

Astad-Solr Astad-User Astad-Request ...

Many modules were created

Only use what you need,Dependencies are explicit!

Easier to test!Each module = one concern

Disadvantages● Still cumbersome to update dependencies

with git tags

Disadvantages● Still cumbersome to update dependencies

with git tags

● BUG = Manually updating package.json of

dependents

(Sinopia)

Our very own private NPM repository

~ Allows patch variations

2. Basic application structure

Basic application structure● Quickly start developing

Basic application structure● Quickly start developing

● Uniformity and familiarity

Skeleton app● Git repository to fork

Skeleton app● Git repository to fork

● Basic uniform file structure

Skeleton app● Git repository to fork

● Basic uniform file structure

● Most used modules included

Disadvantages● Still some basic configuration required

Disadvantages● Still some basic configuration required

● Some apps need frontend, others don’t

Disadvantages● Still some basic configuration required

● Some apps need frontend, others don’t

● Need to remove unused dependencies

Yeoman Generator(s)● Asks basic questions

Yeoman Generator(s)● Asks basic questions

● Conditionally load dependencies,

file structure

Yeoman Generator(s)● Asks basic questions

● Conditionally load dependencies,

file structure

● Basic config taken care of

yo astad Please specify your project name: “A-stad”Do you need a frontend for this project : (Y/n) “Y”

3. Code quality

Testing● Ensure functionality is correct

Testing● Ensure functionality is correct

● Test robustness of methods

Testing● Ensure functionality is correct

● Test robustness of methods

● Tests allow refactoring

Testing without Control● Easy to cheat

Testing without Control● Easy to cheat

● Tests are neglected

Automated testing● No deploys without tests

● PR’s are not approved when tests fail

Other measures● Coding guidelines:JSLint, ESLint

● Code Reviews during PR, min 2 other dev’s.

Conclusion● Reusable modules

● Basic application structure

● Code Quality

ConclusionLearning from your mistakes allows for continuous

improvement and enables you to write better code.

Questions?