Why I Decided to Migrate My JavaScript Project to TypeScript

I’ve been working on this project to support my health tracking and climbing training routine. It’s a project close to my heart. Not just a tool, but a companion for my family's long-term fitness journey. As I started planning its future, I realized that keeping it maintainable and scalable over the years would be a challenge with plain JavaScript. That’s when I decided to take the plunge and migrate my project to TypeScript. Here’s why I made that choice, focusing on one key reason: long-term maintenance.

The Project: A Long-Term Commitment

This isn’t a throwaway app or a quick side project. My goal is to build something I can rely on for years, tracking my nutrition, workout progress, and climbing goals. Over time, I’ll likely add features like data visualizations, goal-setting tools, or even integrations with wearables. With that kind of evolution in mind, I needed a foundation that wouldn’t crumble under the weight of future updates. JavaScript, while flexible and fast to work with, started feeling like a risky choice for a project I want to maintain and grow over the long haul.

Why TypeScript? Long-Term Maintenance

After some research (and a bit of hesitation), I settled on TypeScript for one standout reason: if the project will evolve over years, TS reduces future headaches. Let me break that down.

With JavaScript, it’s easy to write code that works today but turns into a mystery tomorrow. Ever accidentally passed a string to a function expecting a number? In JS, you might not notice until something breaks at runtime, sometimes months later. For a personal project like mine, where I might not touch the code for weeks at a time, that’s a recipe for frustration. TypeScript, with its static typing, catches those mistakes before the code even runs. For example, if I define a function like this:

function logClimbingGrade(grade: number) {
    console.log(`Today’s climb: Grade ${grade}`); 

}

TypeScript will yell at me if I accidentally call logClimbingGrade("V8") instead of logClimbingGrade(8). That’s one less bug to chase down when I revisit the code a year from now.

Beyond catching errors, TypeScript acts like built-in documentation. As my app grows (say, with a TrainingSession interface defining properties like date, duration, and intensity) I won’t have to guess what data I’m working with. The types tell the story:

When I come back to this code after a long break (or if I ever share it with someone else), it’s crystal clear what’s expected. That clarity is gold for long-term maintenance.

This migration is about more than just code. It’s about building something reliable for my future self, a tool I can trust as I push my climbing grades higher and fine-tune my health goals. TypeScript gives me confidence that, even as the project evolves, I won’t be buried under a pile of obscure bugs or forgotten logic. For a long-term companion like this app, that peace of mind is worth every minute spent learning and converting.