Typescript 101

Published: 2/25/2026

When I started learning TypeScript, I used to be very confused.
If it’s JavaScript that the browser understands, and type safety just goes away at runtime, then why even use it?
But when I started creating projects, I realized what it was actually for.

What it solves

Imagine creating an object called `person` that has properties like:

- `name`
- `image`
- `city`

During development, you accidentally mistype:

person.city

as

person.citi

JavaScript doesn’t complain. It just runs your code — and then bam — it crashes, saying it can’t access a property of undefined.

Now imagine you have a large codebase with many developers working on it.
These kinds of mistakes are very common.

And you definitely don’t want to push this type of code to production.

So how do we solve this problem?

We create a contract where we define what a Person should look like — what properties it has and what their types are.

For example:

type Person = {
  name: string;
  age: number;
  city: string;
};

Now, if we create a person object like this:

const p1: Person = {
  name: "alex",
  age: 20,
  city: "mumbai",
};

Anywhere in the code, when you use p1 and try to access its properties:

• You get autocomplete automatically
• If you make a typo, you immediately see an error
• VS Code shows a red underline before the code even runs