5 Things I Learned in My First Week of TypeScript

This content originally appeared on DEV Community and was authored by mashayeakh islam

Hey everyone! I’m Masayeakh, a Full stack Dev from Bangladesh who’s learning TypeScript to level up my skills.

Last week, I started my TypeScript journey — and wow, it’s been an exciting ride so far! From type safety to cleaner code, I can already see why so many developers love it.

In this post, I’ll share 5 simple but powerful lessons I learned in my first week of TypeScript. If you’re starting out like me, this might help you avoid confusion and learn faster

1. TypeScript Catches Errors Before You Run the Code

In JavaScript, many bugs show up only when you run your code.
But in TypeScript, errors appear while you’re writing.

let age: number = "25"; // ❌ Type error: Type 'string' is not assignable to type 'number'

> It’s like having a super strict but helpful teacher who doesn’t let you make silly mistakes.

2. Defining Function Types Keeps Your Code Clean

You can define what type of data a function expects and what it returns.

function add(a: number, b: number): number {
  return a + b;
}

> If you accidentally return a string or forget a parameter, TypeScript immediately warns you.
It makes functions predictable — which is great for big projects.

3. Objects and Type Aliases Make Life Easier
Instead of writing object types again and again, you can use type aliases.

type User = {
  name: string;
  age: number;
  email?: string; // optional property; email will be added if used otherwise blank;
};

const user1: User = { name: "Masayeakh", age: 25 };

> This makes code look cleaner, especially when building apps with many components.

4. Readonly Properties Prevent Unwanted Changes
If you don’t want something to be modified, just make it readonly.

type Config = {
  readonly apiUrl: string;
};

const config: Config = { apiUrl: "https://api.example.com" };
config.apiUrl = "https://newurl.com"; // ❌ Error

> This is small but super useful in team projects where mistakes happen.

5. Union Types Are a Game-Changer
Union types let a variable hold more than one type.

function getId(id: number | string) {
  return id;
}

getId(123);
getId("abc");

> They’re great when your data can come in multiple forms (like user IDs or API responses).

Final Thoughts

My first week with TypeScript taught me one thing — type safety = peace of mind.
It doesn’t just catch bugs early; it helps me write more confident, organized code.

Next, I’ll dive into interfaces, generics, and TypeScript with React — can’t wait to share that journey too!

If you’re learning TypeScript as well, let’s connect and grow together

About Me
I’m a Full Stack Developer learning AI-driven TypeScript, Next.js, and modern web technologies.**
I love building projects, sharing what I learn, and connecting with global devs.
Let’s grow together — both in code and life

This content originally appeared on DEV Community and was authored by mashayeakh islam