LisboaJS Christmas Edition: JS Under Pressure — Resilient Code for Unreliable Conditions 🎅🛷❄️😱
Prepare your ugly Christmas sweaters! We're putting together a LisboaJS with more candy and a rustic dinner afterwards to celebrate the festive season alongside you.
Welcome to LisboaJS, a JavaScript community based in sunny Lisboa. We're building a place where beginner and seasoned developers can come to share, to learn and to laugh together. Join our community on Telegram.
About the Speakers
Faris Aziz, Co-founder at ZurichJS and Staff Software Engineer at Smallpdf
Caching, Payloads, and Other Dark Arts: Optimizing UX in Suboptimal Conditions
We build smooth UX on localhost and stable WiFi, then ship into environments with unstable networks, slow devices and backend APIs we do not control. When the cards are unideal, architecture decisions become the difference between a usable product and a broken one.
This talk explores how to evaluate data flows under stress, handle different API classes, and separate what is critical from what is optional. We start from a setup that technically works but crumbles under real latency, then evolve it into something resilient and intentional.
All demos were recorded on a long haul flight using unreliable in flight WiFi, exposing how brutal real conditions can be. The goal is to rethink how we design data access, not for perfect scenarios but for the harsh reality users actually use them in.
Hugo Sousa, Software Engineering at Altoo
Modern TypeScript applications often become fragile the moment async work, failures, or side effects enter the picture. Runtime errors appear unexpectedly, race conditions creep in, and code that once felt simple becomes difficult to reason about and even harder to test.
While async/await made asynchronous code easier to write, it didn’t solve deeper problems like explicit error modelling, resource safety, retries, timeouts, dependency management, or composability.
Effect is a TypeScript library designed to tackle these challenges head-on. Inspired by Scala’s ZIO, it provides a principled way to build predictable, resilient, and type-safe applications—without sacrificing developer ergonomics.
In this talk, Hugo offers a gentle, practical introduction to Effect. He relates its core abstractions to concepts you already know from everyday JavaScript and helps you learn how to read, reason about, and structure code written with Effect—so it feels less like magic and more like a powerful new tool in your toolbox.
AGENDA
18:30 - Doors open: registration. Snacks & Board games (Exploding Kittens, Taco Goat, Chess)
19:05 - Intro to the LisboaJS Community by Malik.
19:15 - "Caching, Payloads, and Other Dark Arts: Optimizing UX in Suboptimal Conditions" - Faris Aziz (Staff Software Engineer at Smallpdf and Founder at ZurichJS.)
19:50 - "Level up your TypeScript with Effect" - Hugo Sousa (Software Engineer at Altoo)
20:50 - Wrap Up
21:00 - Dinner with Developers at Portuguese Restaurant. You'll be matched with 5 other people.
👋 Give a talk at LisboaJS
If you'd like to share your knowledge with the Lisbon JavaScript community and with the world at large, we're looking for speakers for our upcoming events. You can apply to give a talk here.
Why give a talk at LisboaJS?
We're good hosts! If you're not based here, we'll tour you around and take you to get a steak or bacalhau at the tastiest places in town. YUM 😋
You'll be joining a lineup of awesome speakers that have worked at places like Google, Cloudflare, Databricks, Neon, SingleStore and Cursor.
We practice with you. From doing vocal warm ups to recording you on stage before the event. We'll be your cheerleaders and work alongside you to make you shine.
We have reach beyond Lisbon. Your talk will be recorded and produced by a professional videographer and uploaded to our YouTube channel.