Migrating a Legacy JavaScript Codebase to TypeScript - JSJ 680
JavaScript Jabber5 Kesä 2025

Migrating a Legacy JavaScript Codebase to TypeScript - JSJ 680

In this episode, Dan and I (Steve) dove deep into what turned out to be a surprisingly complex, yet incredibly insightful topic: gradually migrating a massive legacy JavaScript project over to TypeScript. We're talking about nearly 1,000 JS files, 70,000+ lines of code, and years of developer history—all transitioning carefully to a typed, modern future.

Dan walked us through how he started by setting up the project for success before converting even one file—getting CI/CD ready, setting up tsconfig.json, sorting out test dependencies, dealing with mock leaks, and even grappling with quirks between VS Code and WebStorm debugging.

We talked tools (like TS-ESLint, concurrently, and ts-node), why strict typing actually uncovered real bugs (and made the code better!), and why it’s crucial not to touch any .js files until your TypeScript setup is rock solid.

Key Takeaways:
  • Gradual migration is 100% possible—and often better—than ripping the bandaid off.
  • TypeScript can and will catch bugs hiding in your JavaScript. Be prepared!
  • Use VS Code extensions or TS-Node to support your devs’ tooling preferences.
  • Don't underestimate the setup phase—it’s the foundation of long-term success.
  • Start small: Dan's team converted just one file at first to test the whole pipeline.
If you’re sitting on a legacy JS project and dreaming of TypeScript, this episode is your blueprint—and your warning sign.

Become a supporter of this podcast: https://www.spreaker.com/podcast/javascript-jabber--6102064/support.

Jaksot(737)

Beyond JavaScript: Master TypeScript at Scale at SquiggleConf  - JSJ 646

Beyond JavaScript: Master TypeScript at Scale at SquiggleConf - JSJ 646

Dan together with Josh Goldberg, a prominent open-source maintainer and author of "Learning TypeScript, dive into the world of TypeScript and JavaScript with a special focus on the upcoming Squiggleco...

28 Elo 20241h 10min

Deep Dive into Metrics and Monitoring with Prometheus and Grafana - JSJ 645

Deep Dive into Metrics and Monitoring with Prometheus and Grafana - JSJ 645

Dive into a fascinating discussion blending the worlds of literature, gaming, and tech. In this episode, Chuck and Dan explore the intriguing connections between The Hobbit and The Lord of the Rings, ...

20 Elo 20241h 25min

Crafting Code and Community: AI, LeetCode, and Meetups - JSJ 644

Crafting Code and Community: AI, LeetCode, and Meetups - JSJ 644

In this episode, they dive deep into the world of coding, meetups, and the evolving landscape of technical interviews. Join them as they explore the fascinating use of OpenAI's technology for coding a...

13 Elo 20241h 9min

Overcoming JavaScript Load Issues: Import Maps and Performance Enhancements - JSJ 643

Overcoming JavaScript Load Issues: Import Maps and Performance Enhancements - JSJ 643

In this episode, they dive deep into the intricate world of JavaScript loading and web performance. Join the panel with insightful discussions led by Dan, Charles, Steve, and special guest Yoav Weiss—...

8 Elo 20241h 35min

Personal Branding for Developers with Morad Stern - JSJ 642

Personal Branding for Developers with Morad Stern - JSJ 642

The JSJ panel talks with Morad Stern from Wix about personal branding; what it is, why it’s important for developers, and how to build it.LinksObama asks America to learn computer scienceConfiguring A...

30 Heinä 202451min

Making AI Accessible for Developers - JSJ 641

Making AI Accessible for Developers - JSJ 641

In this captivating episode, they dive deep into the world of AI, hands-on learning, and the evolving landscape of development with Steve Sewell from Builder.io. They explore the misconceptions about ...

23 Heinä 20241h 25min

Framework Comparisons, Real User Metrics, and Effective Performance Tools - JSJ 640

Framework Comparisons, Real User Metrics, and Effective Performance Tools - JSJ 640

In today's episode, they dive deep into web performance optimization and the strategies employed by our expert panel to achieve it. Join Dan, Steve, Charles, and guest Vinicius Dallacqua as they explo...

16 Heinä 20241h 19min

Adapting to Effect Cluster: JavaScript Developers' Guide to Enhancing Code Maintainability - JSJ 639

Adapting to Effect Cluster: JavaScript Developers' Guide to Enhancing Code Maintainability - JSJ 639

In today's episode, they dive deep into the world of JavaScript and TypeScript. They explore the innovative message-passing style between components using Effect Cluster, a game-changing alpha product...

9 Heinä 20241h 35min

Suosittua kategoriassa Liike-elämä ja talous

sijotuskasti
psykopodiaa-podcast
mimmit-sijoittaa
rss-rahapodi
rss-lahtijat
rss-draivi
rss-porssipuhetta
rahapuhetta
oppimisen-psykologia
rss-rahamania
rss-seuraava-potilas
rss-neuvottelija-sami-miettinen
rss-bisnesta-bebeja
rss-paatos-podcast-suomen-kovimmat-paatoksentekijat-2
rss-paasipodi
rss-40-ajatusta-aanesta
taloudellinen-mielenrauha
syo-nuku-saasta
kasvun-kipuja
rss-viisas-raha-podi