I resisted TypeScript for years. "It's just more boilerplate," I'd say. "JavaScript is fine for me."
I was wrong.
The Problem with JavaScript
Here's my JavaScript from 2019:
function getUser(id) {
return fetch(`/api/users/${id}`)
.then(res => res.json())
.then(data => {
return data;
});
}What does this function return? A user object? undefined? A promise? An error?
The answer: it's complicated. And that's the problem.
The Turning Point
I was debugging a production issue. A user's name was undefined in one specific scenario. After 6 hours of tracing through the code, I found it:
const user = getUser(id);
console.log(user.name); // undefined!
The function returned a promise, but the caller wasn't awaiting it. Classic async mistake.
TypeScript would have caught this immediately:
interface User {
id: number;
name: string;
email: string;
}
async function getUser(id: number): Promise<User> {
const res = await fetch(`/api/users/${id}`);
return res.json();
}
// Now this is an error:
const user = getUser(1);
console.log(user.name); // Error: Property 'name' does not exist on type 'Promise<User>'
The error happens at compile time, not in production.
What TypeScript Actually Gives You
1. Documentation That Doesn't Lie
interface Project {
id: string;
name: string;
status: 'active' | 'completed' | 'archived';
team: Team[];
createdAt: Date;
}I know exactly what a Project looks like. No guessing. No reading 500 lines of implementation.
2. Refactoring Without Fear
Rename a property? Move a file? Change a function signature?
In JavaScript, you break things and find out later. In TypeScript, you break things and know immediately.
3. Better IDE Support
Auto-complete that actually works. Inline type hints. Go-to-definition for variables. These aren't gimmicks — they make coding faster.
The "Any" Escape Hatch
"But you can just use any!"
Yes. And I did, initially. The escape hatch exists.
But here's the thing: the more you type, the less you need any. The discipline of defining types — even loosely at first — pays off.
My TypeScript Journey
- 2019: Added
// @ts-checkto JavaScript files - 2020: Full TypeScript migration on new projects
- 2021: Retroactively typing old projects
- 2022: Can't imagine starting anything without it
The Verdict
TypeScript isn't about being perfect. It's about being clear. About catching mistakes before they cost you. About having a contract between your code and your future self.
I don't write JavaScript anymore. Not because it's bad — but because TypeScript is better.