TypeScript vs. JavaScript: Which One Should You Use in 2025?

The age-old debate – What’s better for development: JavaScript or TypeScript? Okay, maybe it isn’t an age-old conundrum, but it does make several developers scratch their heads before beginning a web development undertaking. 

Before we dive into these languages (or offshoots of the same language) and discuss their differences as well as which one we believe you should use in your next project, let’s have a look at exploring what they are if you are new to them.

JavaScript is an interpreted programming language that allows us to build amazing features on web pages – at least that’s how it would have been defined a couple of years ago – but JavaScript no longer refers to the programming language that simply aids HTML and CSS in building fabulous websites by controlling the behavior of features. 

Now JavaScript can be used to build standalone applications full of amazing features and do wonderful things thanks to the advent of Node.js. Some of these applications are games and utility programs. You may not realize it, but games like Angry Birds, Bejeweled were built using JavaScript. 

Netflix also relies on JavaScript to a large degree, and even apps like Uber integrate JavaScript into their features, according to this article. So with all the great things JavaScript has blessed us with, we may wonder at what point TypeScript came into the picture. For now, let’s have a look at defining and briefly understanding what it is.

TypeScript is a strongly typed, compiled programming language and a syntactic superset of JavaScript that was developed by Microsoft. All that fancy wording means is that it is a language that is an offshoot of JavaScript, meaning it includes all the features and syntax of JavaScript with additional capabilities. It simply adds static typing to JavaScript. If you are confused by this, do not fret, as we will explore it in detail in the following sections.

We must compare both languages here so that we have a better understanding of their features and where they are best used. In doing so, we can better determine if JavaScript or TypeScript is more appropriate for a feature or project.

As JavaScript developers, knowing both fairly is also crucial. In some projects, you may be forced to use TypeScript instead of JavaScript, and knowing its nuances would help you make better decisions as you code, especially in backend development, where the smallest of decisions could affect an app’s performance.

Getting to Know JavaScript a Little Better

You’ve likely been hearing about JavaScript for some time, but it may surprise you to know that the language was built in just ten days in May 1995. That’s the length of time we may whine over a minor task in less attractive work moments, and in that time, an entire language was built, which is quite amazing. Brenden Eich was the brilliant mind behind this feat with his brainchild initially called Mocha, then LiveScript, and finally JavaScript. HTML was quite a great technology at the time, but it was pretty boring without dynamic elements. 

The introduction of JavaScript meant that web pages could become interactive and a lot more fun to use. In time, JavaScript has gone beyond simply making web pages interactive. 

It is now used to build games and a variety of web applications. It has also undergone numerous revisions with changes introduced in each, the number of revisions comparable only to an average teenager’s change in fashion trends, perhaps. 

How these changes culminated in the birth of TypeScript will be explored soon.

Interesting features in JavaScript

I recall a saying by someone referring to JavaScript as the “drunken uncle of programming languages”. While this is not the most elegant notion to be held of a beloved language, there are reasons for the statement that person, who was me, made.

The Weirdness of NaN

There are memes as far as the eye can see of JavaScript quirkiness, especially regarding NaN, which stands for “Not a number”. It simply means that the value is not a legal number. However, if we were to run the code below, which merely equates NaN to itself, we would get false.

<pre><code class="language-javascript">
Console.log(NaN===NaN) // This returns false

</code></pre>

Like that isn’t weird enough, we deal with the fact that NaN is technically a number.

<pre><code class="language-javascript">
Console.log(typeof NaN) // This would return number

</code></pre>

How Strict is the Equality Operator?

We also find that the equality operator can provide unexpected results:

<pre><code class="language-javascript">
console.log(1 == true); // true
console.log(3 == true); // false
console.log(0 == false); // true
console.log("" == false); // true
console.log("" == 0); // true
</code></pre>

These unexpected results could cause hidden bugs. On account of this, strict equality was introduced (===) but the thing is it is also quirky as you can see below:

<pre><code class="language-javascript">
console.log(+0 === -0); // This returns true
</code></pre>

These are only a few of the many interesting features of JavaScript. They may make you wonder less now about the multiple revisions. However, some of these features are not bugs but rather intentional. For instance, according to the ECMAScript specifications, it is not possible to use === to check for NaN. Instead, you use Number.isNaN() and get the right result.

<pre><code class="language-javascript">
console.log(Number.isNaN(NaN)); // Returns true
</code></pre>

 If JavaScript is the Drunken Uncle of Languages, Why is it So Popular?

That’s a good question, and there are simple answers for it. JavaScript’s greatest edge seems to lie in its versatility. JavaScript may be used to write both the frontend and backend of a web application.  In addition, there is a wide community support. While learning to code in JavaScript, new developers are exposed to a vast number of documentation, articles, videos, courses, and developer communities. With such support, more people are encouraged to pick up the language. It is also relatively easy to learn, a conclusion you may arrive at if, like me, you’ve tried learning Java first.

Use Cases for JavaScript

If you’ve been keenly following the preceding sections, you may have a general idea of the areas JavaScript could be used. For instance, you’ve seen that it is used in building web applications and in game development. You may also find its usage in mobile app development and artificial intelligence. Now you may wonder where TypeScript fits into all of this, especially concerning JavaScript.

An Overview of TypeScript

Some of the nuances of JavaScript we have discussed appear amusing, that is, until you are working on large-scale applications. Granted, you can waddle your way around them with a good knowledge of the language, but it can get pretty exhausting at times. In an attempt to manage these complexities, TypeScript was born in 2012 by Microsoft. The team was led by none other than Anders Hejlsberg, who created C# and Turbo Pascal. Being a superset of JavaScript, TypeScript is an awful lot like JavaScript but not as occasionally absurd. If we consider JavaScript the drunken uncle of the family gathering, TypeScript could be considered his sibling who tries to keep him in check from time to time. Whatever is implemented in JavaScript can be implemented in TypeScript, hence, JavaScript developers are almost always TypeScript developers as well. In the end, TypeScript code is converted into JavaScript using the TypeScript compiler.

Key Features of TypeScript

TypeScript boasts a number of features that extend JavaScript’s capabilities. Here we would be briefly discussing just a few of these features.

Static Typing

In TypeScript, you can specify the types of variables, functions, and return values. This is beneficial for catching errors early in development, i.e., during compilation as opposed to catching them during runtime. This greatly reduces the hassles met with dynamically typed languages, where variable types change, allowing errors to creep out of places you never thought to consider. TypeScript helps us prevent such painstaking debugging, which results from that. Check out the example below:

<pre><code class="language-typescript">
function summonDeveloper(name: string): string {
    return "Hello " + name + " you are summoned! We have coffee.";
  }
  const username: string = "Amanda";
  console.log(summonDeveloper(username));
</code></pre>

You have noted that the username is a string. If you place a number instead, TypeScript will throw a compile-time error because a number (like 33) is not a string.

The Use of Generics

Generics are a neat feature of TypeScript. With generics, your functions, interfaces, and classes are not tied to a specific class, and you can write reusable code with ease. This is great for maintainability, and it’s great to write less code where necessary.

<pre><code class="language-typescript">
function identity<T>(value: T): T {
  return value;
}
 
// Using the generic function with different types
const numberResult = identity<number>(404);     	// number
const stringResult = identity<string>("Amanda");   // string
const boolResult = identity<boolean>(true);    	// boolean
 
console.log(numberResult); // logs 404
console.log(stringResult); // logs Amanda
console.log(boolResult);   // logs true
</code></pre>

Union Types

In TypeScript, we can define types that could be one of several things. For instance, we could define a type named “developerPersona” to be “genius” or “caffeinated keyboard smasher”. In this situation, developer Persona could be either of the two.

<pre><code class="language-typescript">
type DeveloperPersona = "genius" | "caffeinated keyboard smasher";

function describeDeveloper(persona: DeveloperPersona): string {
  if (persona === "genius") {
	return "They write flawless code on the first try.";
  } else {
	return "Fueled by caffeine and rage, but it compiles!";
  }
}
 
// Usage
console.log(describeDeveloper("genius"));                 	console.log(describeDeveloper("caffeinated keyboard smasher"));
// console.log(describeDeveloper("put-together mike")); // Error: not assignable to type 'DeveloperPersona'
</code></pre>

Use Cases and Trends

As we mentioned earlier, TypeScript has a knack for catching errors during compilation. The presence of strong typing and numerous tools also makes it an attractive choice for developers. It is especially used in large-scale applications that may be more prone to errors due to deadlines and angry product managers breathing down the necks of coders. 

JavaScript, on the other hand, may have hidden errors lurking in the codebase on account of nuances, some of which we discussed, but TypeScript keeps that to a minimum with these features. Several well-known companies such as Google, Slack, and Microsoft regularly use TypeScript, and with a growing community and support, a lot more developers are beginning to adopt its use.

How Different are JavaScript and TypeScript anyway?

The impression you may have so far is that the two are simply quite identical, despite one seemingly being an offshoot of the other, and you won’t be far from the truth with that notion. The two languages seem quite similar but also quite different, as you may have gathered from our discourse so far. 

Let’s explore some specific areas where they differ so you can make better informed decisions on what to use in a project.

Typing: Dynamic vs. Static

A difference between JavaScript and TypeScript that stands out is in their typing systems. JavaScript uses dynamic typing, meaning that without prior declarations, we could assign any type to a variable. As we have already seen, this could lead to some subtle bugs that may be hard to find.

On the other hand, TypeScript supports static typing, which means that types are declared explicitly. Errors are therefore caught during compilation, which greatly limits bugs.

Developer Experience: IDE Support and Debugging

This point partly plays on the previous. Debugging is a bit of a hassle with JavaScript because errors are caught at runtime. TypeScript, on the other hand, makes debugging easier since errors are caught at compile time, thanks to its typing system. Regarding the developer experience, modern IDEs such as VS Code support TypeScript’s type system in features like intelligent code completion and real-time error detection.

Learning Curve for Beginners

TypeScript is a superset of JavaScript, meaning it introduces new concepts like generics and interfaces. JavaScript, on the other hand, has a loose syntax that beginners may find to be more approachable. In addition, since TypeScript extends JavaScript’s features, most beginners may find JavaScript to be an ideal starting point to get the basics of programming right before proceeding to more advanced concepts in TypeScript.

Community Support and Ecosystem

JavaScript has been on the scene longer and boasts several libraries, community contributions, and frameworks. It therefore has a more mature ecosystem and community support than TypeScript. However, though relatively new, TypeScript is undergoing massive growth in terms of community backing.

Performance in Real-World Applications

To understand the variation in performance between them, it is important to realize that there is, in fact, no variation. I’ll explain.

TypeScript, in the end, compiles down to JavaScript. What this means is that the same code is ultimately run in browsers or Node.js environments. However, if we are to judge performance based on reduced debugging time on account of reduced bugs and code quality, TypeScript tends to differ from JavaScript and may be said to score higher in terms of performance. So while execution speed remains the same, time debugging is saved, which, if you have spent some time coding, is pretty significant in your book.

Looking at the Code

In our line of work, talk is great, but we’ve got to see the code to truly understand. In order to appreciate the differences that exist between the two languages, we will be taking a look at side-by-side code comparisons of some basic examples, with examples like adding up numbers and error handling. Let’s walk through these examples.

Adding up numbers

Using JavaScript:

As we have seen, one of the nuances of JavaScript is at play here. Without strict type enforcement, errors like the one above may go unnoticed for a while. Also, notice the syntax differences. We are made to declare the types in TypeScript, but this is not enforced for JavaScript.

<pre><code class="language-javascript">
function addAnimals(specie1, specie2) {
  return specie1 + specie2;
}
console.log(add(5, "10")); // Output: "510" -- no error, but likely unintended
</code></pre>
Using TypeScript:
<pre><code class="language-typescript">
function addAnimals(specie1: number, specie2: number): number {
  return specie1 + specie2;
}
console.log(add(5, "10")); // Error: Argument of type 'string' is not assignable to parameter of type 'number'
</code></pre>

Handling classes

Using JavaScript:

<pre><code class="language-javascript">
class Person {
  constructor(name, age) {
	this.name = name;
	this.age = age;
  }
}
</code></pre>
Using TypeScript:
<pre><code class="language-typescript">
class Person {
  name: string;
  age: number;
 
  constructor(name: string, age: number) {
	this.name = name;
	this.age = age;
  }
}
</code></pre>

As we’ve mentioned, Type annotations occur in TypeScript but not so in JavaScript.

Dealing with errors

In JavaScript:

<pre><code class="language-javascript">
 try {
  JSON.parse("invalid json");
} catch (error) {
  console.log("Oops. Something went wrong:", error.message);
}
</code><pre>
 TypeScript:
<pre><code class="language-typescript">
 try {
  JSON.parse("invalid json");
} catch (error: unknown) {
  if (error instanceof Error) {
	console.log("Oops. Something went wrong:", error.message);
  }
}
</code></pre>

 try/catch and instanceof are important built-in methods that help us with error handling.

Fetching data with async/await

In JavaScript:

<pre><code class="language-javascript">
 async function fetchDevInfo() {
  const response = await fetch("https://api.example.com/dev");
  const data = await response.json();
  return data;
}
fetchDevInfo().then(dev => console.log(dev));
</code></pre> 

TypeScript:

<pre><code class="language-typescript">
type Dev = {
  id: number;
  name: string;
  email: string;
};
 
async function fetchDevInfo(): Promise<Dev> {
  const response = await fetch("https://api.example.com/dev");
  const data = await response.json();
  return data as Dev;
}
fetchDevInfo().then(dev => console.log(dev.name));
</code></pre>

 Async/await functions using fetch also show a difference between languages. While concise, JavaScript provides no guarantees about the structure of data, which can lead to runtime issues if the response shape is unexpected. With TypeScript, we explicitly define the structure of the response. This not only improves readability but also prevents bugs by catching type mismatches during development.

Pros and Cons Summary Table

If you’re short on time, this table could help you make a decision quickly on what to choose for your project, based on the pros and cons:

You could consider it a cheat sheet or quick lookup. Now we move on to more pressing matters regarding JavaScript’s utility.

Is JavaScript Going Extinct?

This has to be the most amusing take on a programming language we have heard and seen in our time as developers, but we know of developers who would strike a table in true melodramatic style, announcing the dying of JavaScript. 

Let’s look at it this way: JavaScript is not a language that could just die away despite its nuances. It can be compared to a fabulous and stylish man with TypeScript being just one of his amazing outfits. If this article has personified JavaScript to be a drunken, stylish man, then my work is complete.

On a serious note, however, JavaScript is a language that is continually evolving. The most intriguing thing about the language is that there are new revisions constantly attempting to improve or extend its features. TypeScript is not a distinctly separate language with improved capabilities, it is simply an extension of JavaScript.

So why all the TypeScript hype?

People like new and shiny things. When developers struggle with those famous JavaScript nuances and someone shows up with something that corrects some of those flaws, they tend to jump on the improved version. That’s a natural response. TypeScript enforces a strictness that JavaScript lacks; it catches errors at compile time and enforces structure. This improves maintainability and reduces debugging time, which makes it a very attractive option for developers.

Where JavaScript still shines

In truth, JavaScript still pretty much runs the show. As we mentioned earlier, under the hood, after all the Krav Maga (you can look this up, it’s a pretty cool way to fight) of TypeScript, it is still compiled to JavaScript for execution. 

It is also a solid choice in situations where flexibility is crucial. Note too that nearly every browser runs JavaScript out of the box without all the hassle of config files and compilation. So while TypeScript seems a smart choice a lot of the time, saying JavaScript is going extinct is more than a stretch, it’s an escape to a space where no physical laws make sense.

Summary

JavaScript and TypeScript each bring unique strengths to the table. JavaScript is battle-tested, universally supported, and ideal for quick prototypes, lightweight apps, or when working with teams deeply involved in its ecosystem. TypeScript, on the other hand, offers powerful tooling through static typing, better IDE support, and error management techniques that make it ideal for large projects and teams prioritizing maintainability and early bug detection.

If you're building something small or need to move fast, JavaScript might still be your best bet. But if you're laying the foundation for a long-term project or want fewer debugging nightmares down the road, TypeScript may just be a better choice.

In the end, one thing to hold dear is that JavaScript isn’t going extinct; TypeScript is just helping it evolve. The future lies not in choosing one over the other, but in knowing when and why to use each, and if you’ve got a friend who persists that JavaScript is going extinct even after showing them this article, well, make a new friend.