The Major Differences Between Typescript and Javascript

Dec 21, 2021

8 Min Read

Brendan Eich and the Technical Committee of the EMCA created JavaScript, a scripting language. It works flawlessly in web browsers without the assistance of a web server or compiler. It lets you edit HTML and CSS in your browsers without refreshing the whole page because it creates dynamic, interactive websites.

The TypeScript language is a JavaScript superset. Anders Hejlsberg, a Microsoft technical fellow, presented and built it in 2012. Typescript was created because as JavaScript gained popularity, js code got heavier and more difficult to understand. It became particularly apparent when programmers began to employ JavaScript for server-side technologies.

TypeScript is a programming language that is both free and open-source with a compiler that translates TypeScript code to JavaScript code. It’s a cross-browser compiler that’s also free and open-source. You may start utilizing TypeScript by renaming your.js files to.ts files and assuming the js code has no logical errors, and you will obtain proper TypeScript code. So TypeScript code is essentially JavaScript code (and vice versa) with a few differences. Watch the original TypeScript video presentation to learn more about the new features. Meanwhile, in 2020, we compare and contrast js and ts.

JavaScript vs. TypeScript: A Brief Comparison

There hasn’t been much progress in JavaScript and TypeScript technology (and hence distinctions between them). So don’t worry if you’re already acquainted with them; your knowledge remains current.

But there is one black swan the world has never seen before. It’s a coronavirus that has changed the whole globe, not just the IT industry. Companies moved to remote working, and economies have been cut off from one another for months, and some still are. As a result, the global value chain for hardware manufacture was disrupted. Even if facilities are reopened and deliveries are restarted, it will take time for manufacturing to resume. In addition, the software may probably become the technology sector’s development driver soon, increasing the need for software programmers. We foresee growth in small and big projects, so choose whichever language you want: JavaScript, which is ideal for developing simple projects in small teams, or TypeScript, which is built to work with large projects in global teams.

JavaScript vs. TypeScript: Major Differences

Type System

The first and most crucial topic to discuss is a type system. JavaScript uses dynamic typing. Because JavaScript doesn’t know the type of a variable until the code runs, you can theoretically do anything you want. However, you get annoying issues when attempting to utilize variables with the incorrect types for specific instructions. One of the tools JavaScript gives to combat this problem is the “use strict” option, which prevents you from using undeclared variables and produces an error for every assignment to a non-existing variable/ property/object.

In contrast, TypeScript employs static typing. The TypeScript type system includes enums, interfaces, hybrid types, union/intersection types, generics, access modifiers, and more. You can’t use variables that aren’t specified, either.

Dynamic typing provides additional flexibility by enabling programs to execute code while avoiding minor mistakes that static type does not allow. It reduces development time, makes understanding JavaScript simpler, and reduces the number of lines of code. However, as we’ve seen, dynamic typing may lead to the issues we’ve discussed. Debugging is challenging since JavaScript attempts to execute the code despite the run-time faults.

TypeScript’s advanced static type system helps prevent this, but it takes longer to build a codebase with good strict typing. However, one of the purposes of TypeScript’s creation was to aid with early error detection and development efficiency.


TypeScript code must be compiled, but JavaScript code does not. After compilation, TypeScript code becomes pure JavaScript, primarily a development tool.

Client and Server Sides

Some individuals compare JavaScript with TypeScript in terms of client/server use, claiming that js has an edge since it is client and server-side, but ts isn’t. That is an inaccurate comparison, in our opinion, since TypeScript code compiles to pure JavaScript that can be used on both the server and the client. So don’t be concerned about the discrepancies here.

Declaration Files

The crucial thing to remember is that TypeScript follows the JavaScript type system closely and only enables you to define what is happening in JavaScript statically. Understandably, declaration files specify a semantic subset of JavaScript libraries.

If you’re unfamiliar with declaration files, they’re just files with the d.ts. The extension contains declarations of modules and namespaces, with a module being any file that includes values, functions, or classes. And we’re talking about declarations, not implementations. When you let your code run through the TypeScript compiler, it generates those files automatically. When TypeScript code is compiled, it transforms into pure JavaScript code with all of the original code’s functionalities. Sharing JavaScript code and a declaration file enables developers to utilize the original code even if TypeScript code isn’t present. To put it another way, declaration files aid in the distribution of js libraries.

You may learn more by cloning the “DefinitelyTyped” repository on GitHub, which contains all of the most popular libraries. In addition, you’ll appreciate how helpful declaration files are when you need to utilize external script files in ts.

Completing your editor is another aspect of declaration files that might be useful. It will reduce the amount of time you spend developing and make coding easier.

Because JavaScript does not utilize declaration files for converting code, they need the TypeScript compiler and your TypeScript code.

The Scope of the Projects

TypeScript is a programming language that enables programmers to build more consistent, clear, simple, and reusable code. Furthermore, typeScript code is significantly simpler to maintain and distribute thanks to static typing and declaration files. In addition, TypeScript is helpful for bug prevention since it saves time combing through code for a foolish error. For big projects, it is thus preferable to utilize TypeScript.

Should TypeScript be used in every project? No.

You can’t debug TS code in a browser, but you can with JS. It is hard to skip the build phase (which takes time) in TS, while there is no need to wait in JS. In TS, you can’t create code fast since you have to define everything, but in JS, you can write any code you want, and it will function as long as it doesn’t include any logical flaws. JavaScript is ideal for essential online apps, and this will continue to be valid for a long time.


Based on Stack Overflow, salaries for TypeScript and JavaScript developers are comparable in the United States and throughout the globe. For example, companies in the United States pay TypeScript engineers $120K per year, whereas they pay JavaScript developers $8k less.


TypeScript is compatible with a wide range of IDEs, but JavaScript is not. For most developers, it’s a must-have tool for writing and testing code, and it makes refactoring a breeze. When you use an IDE, you receive intelligent code completion and error detection as you write, which dramatically speeds up the coding process. Visual Studio Code, WebStorm, and Atom are the finest and most popular IDEs.


  • Type System: Static Typing
  • Compiler: Compilation is required
  • Declaration Files: TypeScript code and the TypeScript compiler both need declaration files
  • The Scope of the Projects: For big projects, TypeScript is preferable
  • IDE’s: It works with a variety of IDEs


  • Type System: Dynamic Typing
  • Compiler: Compilation is not required
  • Declaration Files: No declaration files are used in JavaScript
  • The Scope of the Projects: JavaScript is ideal for developing essential web apps.
  • IDE’s: Supports a substantially smaller number of IDEs

So, which option should you take?

For Beginner

It’s a good idea to start with learning JavaScript. However, after you’ve learned the foundations, you should go to TypeScript. The most challenging aspect of TypeScript is the learning curve. Yes, TypeScript provides several valuable tools for managing, sharing, debugging, and writing code, but to utilize them effectively, you must first understand how they function. Furthermore, since TypeScript is a superset of JavaScript, you must first grasp JS before moving on to its more complex counterpart.

For Mid Developer

It’s time to learn TypeScript if you don’t already know it and want to work on more complex projects. On the other hand, JavaScript is acceptable if you are an experienced developer who works on relatively modest coding projects and in small teams. In addition, there is no financial motivation to transition to TypeScript since salaries are almost identical. On the other hand, Typescript becomes a better alternative if you have the expertise, ideas, or a requirement for team growth.

For Senior Programmer

So, you’ve already mastered JavaScript and TypeScript, and we’re betting you’re an expert in both. You don’t have to choose one, and the only thing you need to know is that nothing will change in those technologies this year.

Typescript vs. Javascript: Review

JavaScript is a simple language to pick up. However, TypeScript has a steep learning curve and needs previous scripting experience. Airbnb, Codeacademy utilize JavaScript, and Instagram, among others, whereas TypeScript is used by Asana, Clever, Screen Awards, and others. In contrast to JavaScript, TypeScript enables static typing, which allows you to type-check at build time. The compiler minimizes the possibility of “dumb” errors like missing commas and misspelled variable names. Still, it also destroys the elegance of JS when most solutions could be written on their knees and tested in the browser console.

TypeScript’s strong typing enables you to specify the properties and methods of objects and classes more completely, eliminating the need to validate every parameter provided in a process or function, which may be pretty inconvenient for sure developers. Because it is essential to explain all kinds of objects, classes, and variables, which was not typical of JavaScript earlier, this item works both for good and evil.

Because there is no tangle of code as in Javascript, the code in TypeScript will be simpler to read. However, it should be mentioned that using abstractions in JS substantially simplifies the code perception.

It should be emphasized that JavaScript appeals to a large number of people. However, as soon as they begin to study it, they notice a sort of instability and unpredictability in the language. If you prefer TypeScript, you can easily convert your favorite libraries from JS to TS. Migration of popular JS solutions to TS, on the other hand, incurs human expenditures. You see, for each ported lib, you must describe the.d.ts file, which has all the returned types and a description of all the methods. However, it takes much more work to port beasts like jQuery, for example. That maybe this isn’t so difficult after all. Every prominent IDE, including IDEA, WebStorm, Sublime, Atom, and others, now supports TypeScript. As a result, you won’t have to switch to a new development environment.


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