Typescript vs Javascript: Comparison, Difference and Applications

By | December 30, 2021

Everyone associated with web development is familiar with JavaScript. It is a popular scripting language used for many web projects. Along with JavaScript, TypeScript is a popular programming language for web development.

This article highlights the key dissimilarities between TypeScript and JavaScript. Also, we will make you familiar with JavaScript and TypeScript along with their pros, cons, and applications.

What is JavaScript? 

JavaScript (JS) is a high-level object-oriented scripting language for developing interactive web pages. It was primarily a client-side language, but the development of Node.js has made it possible to execute the JS code on the server-side.

The syntax of JavaScript is analogous to Java. Also, it is the commonly used language with HTML and CSS in web development. While HTML and CSS provide structure and style to web pages, respectively, JavaScript makes the elements of a web page interactive and dynamic. It is a just-in-time (JIT) compiled language that follows functional, imperative, and event-driven programming paradigms.

Designed by Brendan Eich at Netscape, JavaScript first appeared in December 1995. In the following year, JavaScript was submitted as a standard specification to the European Computer Manufacturers Association (ECMA) International. Later the year 1998 witnessed the release of ECMAScript 2, and 1999 saw the release of ECMAScript 3.

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The development of ECMAScript began in the 2000s, but it never reached fruition. In 2009, an incremental upgrade to ECMAScript 3 was introduced, called ECMAScript 5. The same year witnessed the creation of Node.js that made it possible to execute JS code on the server-side. Node.js is a JavaScript runtime environment running on Google Chrome’s V8 engine. In 2016, ECMAScript 6 was published.

Pros of JavaScript

The following are some significant advantages of JavaScript:

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  • JavaScript is a just-in-time (JIT) compiled language, which means that the compilation of the code takes place at the runtime or during the execution of a program. Therefore, it saves the time required for compiling the code.
  • It is one of the most popular scripting languages compatible with all modern web browsers, such as Safari, Google Chrome, Opera Firefox, and Internet Explorer.
  • JavaScript is interoperable, meaning that we can use it with other programming languages and embed it in web pages.
  • It is a versatile language, enabling developers to use it for the front-end as well as back-end development. Node.js helps in back-end development, whereas libraries, like ReactJS, AngularJS, etc., help in front-end development.
  • It reduces the code length and improves the performance of websites and web applications.

Cons of JavaScript

The following are the downsides of JavaScript:

  • JavaScript only supports single inheritance and not multiple inheritances.
  • It becomes challenging to develop large applications using JavaScript.
  • As the JS code is visible to users, hackers can use it for malicious purposes.
  • JavaScript operators operate on 32-bit bitwise operands, and it stores a number as a 64-bit floating-point number. As a result, JavaScript needs to convert numbers into 32-bit signed integers, operate on them, and finally, convert them back to 64-bits JS numbers. Therefore, it is a time-consuming process and reduces the speed.

Applications of JavaScript

  • Web development
  • Game development
  • Mobile application development
  • Web servers
  • Presentations as websites
  • Smartwatch applications
  • Flying robots

What is TypeScript?

TypeScript and JavaScript share a similar purpose, but the only difference is that the former is ideal for developing large web applications, whereas the latter is the best choice for developing small web projects. It is a superset of JavaScript having a more strict syntax and adds optional static typing to the language. TypeScript is specially designed for developing large applications and transcompiling them to JavaScript.

Transcompilation or source-to-source compilation is a translator accepting the source code of a program scripted in one programming language and producing an identical source code in the same or different language. We can use the TypeScript Checker compiler, which is the default one for transcompilation. Else, we can opt for the Babel compiler.

In 2012, TypeScript was made public as version 0.8. The next version of TypeScript 0.9 was released in 2013 and it included the support for generics. TypeScript 1.0 was released in 2014, which was supported by Visual Studio 2013 Update 2.

TypeScript 2.0 was released in 2016 and introduced a feature of a billion-dollar mistake. A billion-dollar mistake allows programmers to optionally prevent variables from being assigned null values. 

In 2018, TypeScript 3.0 was made public and brought many language additions, like rest parameters with tuple types, generic rest parameters, tuples in rest parameters and spread expressions, etc. Finally, TypeScript 4.0 was released in 2020, which added language features, such as Variadic Tuple Types and Custom JSX Factories.

Pros of TypeScript

The following are the benefits of TypeScript:

  • In TypeScript, everything stays the way we define it since it follows strict typing. For example, if you want a variable to always be a number, it is achieved through strict typing.
  • While working with TypeScript, we get compilation errors while developing an application and not at runtime. Therefore, there are very few chances of getting errors at the runtime.
  • It is possible to convert TypeScript code into JavaScript code.

Cons of TypeScript

Below are some major drawbacks of TypeScript:

  • TypeScript has a steep learning curve. Also, you first have to learn JavaScript and then learn TypeScript.
  • It takes a significant time to compile TypeScript code.
  • It does not support abstract classes.

Applications of TypeScript

TypeScript has the same applications as JavaScript. Additionally, it is used for developing complex web applications, whereas JavaScript is not.

JavaScript vs TypeScript: Head to Head Comparison

The below table highlights the major dissimilarities between JavaScript and TypeScript:

JavaScript  TypeScript
JavaScript is a scripting language used for developing dynamic web pages. TypeScript is a superset of JavaScript and is designed to develop large web applications.
We can encounter errors at the runtime since JavaScript is an interpreted language. We can find errors and correct them at the compile time in TypeScript.
It is a weakly-typed language and does not support static typing. It is a strictly-typed language and supports both static and dynamic typing.
JavaScript is used directly in browsers. TypeScript is first converted into JavaScript, i.e., it transcompiles to JavaScript and then runs in browsers.
It does not support modules, generics, or interfaces. It supports modules, generics, and interfaces to define data.
Numbers and strings are objects in JavaScript.  Numbers and strings are interfaces in TypeScript. 
It does not support prototyping.  It supports prototyping. 
JavaScript does not require any build setup.  TypeScript requires the build setup for static type definitions. 

JavaScript vs TypeScript – Which One to Choose?

TypeScript is ideal for developing complex web applications, all thanks to the types and decorators that it offers. The feature of decorators is essential for frameworks like Angular, Nest.js, etc., since it separates the modification or decoration of a class without affecting the original source code. Also, Angular comes with various tools, boilerplate, and starter packs, making it easier for developers to set up or build their web projects quickly and effortlessly.

Sometimes, TypeScript becomes exorbitant and time-consuming for small web applications, as it needs to transcompile the code to JavaScript and type-check it. In such cases, it is beneficial to use JavaScript. Also, TypeScript needs a proper setup and an IDE to execute the code, whereas JavaScript runs directly on the browser.

Conclusion

Here we have reached the end of the topic. JavaScript and TypeScript have their own features and limitations. TypeScript is a comprehensive language, allowing developers to write clean, compact, and readable code. Static typing and live-error checking features make TypeScript a more powerful language. But, it is not native to all web browsers, like JavaScript.

On the other hand, JavaScript is a widely-used language native to all web browsers. Though it is not a comprehensive language like TypeScript, many experienced developers prefer using JavaScript for creating dynamic web pages. 

We hope this article covered all the basic differences between JavaScript and TypeScript. We recommend you to go for JavaScript for small web projects and TypeScript for huge web projects.

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