Is TypeScript Faster than JavaScript?

So, is TypeScript faster than JavaScript? Well, it is actually a fairly tricky question to answer that requires some top-notch technical knowledge. Luckily for you, I am going to explain it.

TypeScript is a language that depends on JavaScript to work. Without JavaScript, TypeScript couldn’t exist. When you write TypeScript code, it will automatically translate to JavaScript at runtime.

Since TypeScript converts to JavaScript at runtime, is it safe to assume it will run equally as fast as JavaScript, right?

Well, it is a bit more complex than that. There actually is a flaw in JavaScript that TypeScript addresses. This enhancement increases the quality of JavaScript code. In doing so, it also improves execution time.

But how? Let’s dive in.

What is JavaScript? 

JavaScript is a popular programming language that almost all programmers are familiar with due to its functionalities. It is a top programming language that allows you to create a myriad of different software. JavaScript is most commonly used to build dynamic and interactive web applications in the browser. 

What is TypeScript? 

Being a “superset of JavaScript,” TypeScript is a more comprehensive version of JS. TypeScript is a free and open-source static typing extension for JavaScript that was created and maintained by Microsoft. Code written in TypeScript converts to JavaScript, meaning it can run on any platform that JavaScript runs on. Despite some confusion online, TypeScript is a programming language.

How Is TypeScript Faster To Run Than JavaScript?

When comparing TypeScript and JavaScript, there are a few things that demonstrate that this claim is accurate. 

To begin, the primary goal of TypeScript is to make the code understandable for the interpreter. It achieves this by verifying that the code is error-free before runtime.

One of the primary ways TypeScript does this is by checking for static errors before the transpiled JavaScript code is run. So after transpiling down to JavaScript, part of the work has already been done. Alternatively, when running JavaScript code, the compiler might encounter errors, which slow down the process.

Type inference and type-checking are two TypeScript features that can help with error detection and overall code quality enhancement. Because TypeScript supports static typing and eliminates run-time errors, the code is more logically structured and operates more efficiently.  The easier the code is to maintain, and the more error-free the code is before runtime, the better the performance.

How Is JavaScript Faster to Write Than TypeScript?

Although TypeScript has a slight speed advantage when executing code, it takes quite a bit more time to write. At least, it does initially.

When you write TypeScript code, you need [or should] declare each type you use. Doing so results in a lot more code being written by the end of your project.

However, you know what they say, “you write your code once, you maintain it for a lifetime”.

Even though TypeScript may be slower to initially write than JavaScript, having declared types in your code and static checking makes your code much easier to write and maintain. It also helps you avoid annoying bugs from undeclared types in the first place.

So really, TypeScript could be faster or slower to write than JavaScript based on how you frame the two languages.

Conclusion

In terms of both execution speed and device scaling, TypeScript is faster and more effective than JavaScript. Its ability to detect errors and bugs at the compilation stage rather than the runtime is the main reason it outperforms JavaScript in terms of performance.

However, it will take you longer to write TypeScript code over JavaScript code. So there are some trade-offs to using TypeScript over JavaScript if you want to reap its benefits.

As always good luck, and happy coding!