TypeScript VS JavaScript : Key Differences You Must Know


Published On:

  September, 12, 2022
Read Time 14.67 Minute Read
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TypeScript VS JavaScript : Key Differences You Must Know

TypeScript and JavaScript are the two leading technologies that play a vital role in web application development. As a result, JavaScript has been the most popular programming language among the developer community.

But, with the invention of TypeScript, the picture has changed completely. Do you know how? TypeScript is considered the enhanced version of JavaScript with some additional features.

Before we understand the difference between TypeScript VS JavaScript, we need to understand the basic concepts of TypeScript and JavaScript.

What is JavaScript?

JavaScript is a client-side and server-side programming language. The primary reason that JavaScript is a scripting language is that it’s not compiled before execution. Instead, the primary usage of JavaScript is to create dynamic web pages.

HTML and CSS are the two major languages that provide structure and style to web pages. On the other hand, JavaScript will provide you with web pages with interactive elements that improve user engagement.

What Is JavaScript Used For?

Javascript is one of the best scripting languages used explicitly by developers globally for creating dynamic and interactive web content-like applications. Almost 97% of all websites primarily use JavaScript as a scripting language.

JavaScript is a boon for developing different applications like software, hardware controls, and servers. In addition, due to its native behavior to the web browser, JavaScript is considered a well-known web-based language.

JavaScript is used for:

  • Easily adding interactive behavior to web pages.
  • Creating web and mobile apps.
  • Building web servers and developing server applications.
  • Speeding up the performance of the application.
  • Developing front-end development as well as back-end development.
  • Performing the data validation on the web browser itself rather than on the server.

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What is TypeScript?

Developed by Microsoft, TypeScript is an open-source programming language that quickly compiles to JavaScript. TypeScript is not just a language but also a set of tools that help you make web development easier.

what is typescript

From the above diagram, we can easily see that TypeScript is JavaScript with additional features designed explicitly to overcome JavaScript setbacks. It is beneficial to the developers regarding static typing and handling code complexity.

What is TypeScript Used For?

TypeScript is a superset of typed JavaScript that allows developers to build and manage large-scale JavaScript projects. In simple words, we can say that it’s JavaScript with additional features like strong static typing, compilation, and object-oriented programming.

TypeScript is used for:

  • Simplifying JavaScript code, making your application easier to read and debug.
  • Quickly building web applications using highly productive development tools for JavaScript IDEs and practices, like static checking.
  • Quickly coding for all complex and large applications.
  • Availing all the benefits of ES6 (ECMAScript 6), plus more productivity.

What are the Different Types of TypeScript?

TypeScript is a programming language that specifically contains various basic types, such as Number, Array, Tuple, Boolean, String, and many more. It’s a fact that some of these essential types are not available in JavaScript. If you want to know more about such types, you can visit the official TypeScript documentation.

Furthermore, below are some other types that are expressivity of TypeScript:

  1. Any & Unknown

    Any (anything that you wish) is best used for covering unknown is its type-safe system. The primary usage of any is to allow the developers to easily assign JavaScript variables. It’s widely used to describe incoming variables that are not yet being validated and whose type is unknown.

    And if we talk about Unknown, it’s exactly similar to Any, but it will not allow you to do anything with it unless it’s explicitly type-checked.

  2. Void

    Void is specifically used by developers when there is no value returned. Generally, it’s used for the return type of function that returns nothing.

  3. Never

    If something is never going to happen, we can use Never as the return type. One such good example is an exception-throwing function.

  4. Intersection & Union Types

    This option allows the developers to easily create custom types as per the logic. Intersection types let you combine several basic types into one type.

    Let’s say, we have custom type Employee which contact empl_fname:string and empl_fname:string. And you want to convert this type to this and that.

    Union types allow you to type to take one of the various basic types.

    For example, if developers pass a query that returns either result:string or undefined, we can definitely say that this type needs to be converted to this or that.

    All of these sorts make sense when you think of them as spaces.

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How Does TypeScript Differ from JavaScript?

As stated earlier, TypeScript has additional features compared to JavaScript programming language. In simple words, TypeScript is an object-oriented programming language, whereas JavaScript is a scripting language.

TypeScript is one programming language bundled up with multiple interfaces and modules through ES6 features; however, JavaScript doesn’t offer such features.

Moreover, TypeScript is strongly-entered, or we can say that it supports static typing. This means static typing permits checking type accuracy at compile time.

TypeScript highlights the compilation errors at the time of development. Due to this, the scope of examining errors is very low at runtime. On the contrary, JavaScript is an interpreted language.

TypeScript is nothing but a JS and some added features, that is, ES6 features. Therefore, many JS developers do not prefer to keep it in their targeted web browser, but the TS compiler can compile .ts files into ECMAScript.

TypeScript VS JavaScript: Pros and Cons

Pros and Cons of TypeScript

Pros Cons
It supports strong static typing TypeScript is not a true statically typed language.
Easily detect bugs at the compile stage Supports enhanced code readability
With TypeScript, everything stays the way it was initially defined. TypeScript typically requires code compilation at every phase
TypeScript codes are more self-expressive Unit tests are no longer instant
Rich IDE support Non-TS libraries require types

Pros and Cons of JavaScript

Pros Cons
just-in-time (JIT) compiled language JavaScript code is viewable to the user, making it used for malicious purposes.
Compatible with all modern web browsers, such as Safari, Google Chrome, Opera Firefox, and Internet Explorer. The browser interprets JavaScript differently in different browsers. Thus, the code must be run on various platforms before publishing.
Interoperable: meaning that we can use it with other programming languages and embed it in web pages. Many HTML editors support debugging, it is not as efficient as other editors like C/C++ editors. Also, as the browser doesn’t show any error, it is difficult for the developer to detect the problem.
Versatile language A single code error can stop the rendering of the entire JavaScript code on the website.
Minimizes the code length The continuous conversions take longer in the conversion of a number to an integer.

TypeScript vs JavaScript Examples

Here we are bringing TypeScript vs JavaScript examples. Now, we will focus on some code snippets to differentiate between TypeScript and JavaScript.

Have a look at the simple and valid JavaScript snippet:

let var1 = “Welcome to Albiorix”;
var1 = 30;

Here, we can see that var1 is a string, then becomes a number.

As we know that JavaScript is only a loosely typed programming language, it becomes easy for the developers to redefine var1 as a variable of any type—from a string to a function—at any time.

So, the output of the code becomes 10.

Now, we will convert the same code to TypeScript:

let var1: string = “Welcome to Albiorix”;
var1 = 10;

Likewise, var1 is declared to be a string. And we are trying to assign a number to var1. This is strictly not allowed by TypeScript’s strict type system. Obviously, the transpiling results in an error:

TSError: ⨯ Unable to compile TypeScript:
src/snippet1.ts:2:1 – error TS2322: Type ‘number’ is not assignable to type ‘string’.2 var1 = 10;

If we want to make the same JavaScript code to behave the same like TypeScript, it becomes mandatory to inform transpiler to treat the original JavaScript snippet as if it were TypeScript. So, it becomes the prime responsibility of the transpiler to automatically infer that var1 should be a string | number.

This is a TypeScript union type, which allows us to assign var1 a string or a number at any time. Having resolved the type conflict, our TypeScript code would transpile successfully. Executing it would produce the same result as the JavaScript example.

Difference Between Typescript and Javascript: The Comparison Table

After having a look at the basics of TypeScript and JavaScript, it’s time to see the comparison in terms of the difference between TypeScript and JavaScript.

Features TypeScript JavaScript
Type Strongly-typed object-oriented programming language Light-weight, interpreted programming language
Creator Anders Hejlsberg Brendan Eich
Server Type Client-side Client-side and server-side
Best For Developing large or complex applications Developing small-sized applications
Compiler Code compilation converts your TypeScript code to JavaScript code It’s completely an independent language
Learning curve Steep learning curve Easy to learn
Supports Supports modules, generics, and interfaces Does not support modules, generics, or interfaces
Prototyping Prototyping feature is available No support of Prototyping

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When to Choose JavaScript and TypeScript?

In the comparison of JavaScript VS Typescript, it’s time to explore the situation for the developers to select TypeScript or JavaScript for their project requirements.

You can opt for the TypeScript programming language when

  • Compile Time Type Checking: TypeScript usually supports Vanilla JavaScript, and in such cases, type verification is performed at runtime. It eventually adds to the runtime overhead, which may be avoided by conducting compile-time validation.
  • Large-Scale Projects: TypeScript is a programming language that is designed explicitly to develop large applications that run seamlessly or when many developers are working together.
  • Easy to Use: If the developers are involved in React development and are not familiar with its APIs, you can utilize IntelliSense, which helps them identify and navigate new interfaces. However, they both offer type definitions.

On the other hand, JavaScript helps you when

  • Small Projects: JavaScript programming language is a perfect choice if you are dealing with small projects or with fewer codes available on the project.
  • Active Framework Support: If TypeScript does not support any common framework like EmberJS, then the developers might not be able to leverage its features.
  • Build Tools: When the developers are in deep need to generate the final run of the JavaScript application, TypeScript requires a build step. However, developing JavaScript applications without any build tools is becoming increasingly unusual.
  • Testing Workflow: If JavaScript developers are involved in utilizing test-driven development, the benefits of switching TypeScript may not be enough to justify the expenditures.

TypeScript VS JavaScript: Which is Better?

Selecting TypeScript over JavaScript makes it easy for the developers to deal with removing certain software anomalies during the development phase. Moreover, you can easily secure the code before going into production.

In this article on TypeScript vs JavaScript, we have seen the overall difference between typescript and javascript & the available essential features of both technologies JavaScript and TypeScript. Moreover, we came across the terminology on how Javascript and Typescript differ.

Hardik Thakker is a Co-Founder & CEO at Albiorix Technology. Having more than 10+ years of experience in handling the development team at a pace, he is totally involved in managing the overall aspects of the full-stack development processes. He completely believes in following Agile methodology and maintaining source code at the highest level of quality efficiency.

Frequently Asked Questions

Is TypeScript better than JavaScript?

As we know that Typescript is a superset of Javascript. In simple words, all the essential JavaScript features are included along with some additional features. Select the best from both, it entirely depends on the project requirements. For example, if you have a smaller project, JavaScript is the best option; otherwise, you can go for TypeScript.

Is JavaScript an Object-Oriented Programming (OOP) language?

JavaScript is a scripting language that conforms with ECMAScript specifications. ECMAScript is a standard for scripting languages.

Is TypeScript front-end or back-end?

TypeScript is both front-end as well as back-end.

How is TypeScript converted to JavaScript?

The web browser typically does not understand the Typescript code. It just needs to first be compiled into JavaScript before execution. Typescript code is thus transpiled to equivalent Javascript code using TypeScript compiler or Babel.

Is TypeScript the best option for Frontend or Backend?

Yes, TypeScript is can be easily used for both front-end as well as back-end. The primary reason behind is that TypeScript can be compiled into JavaScript. Moreover, JavaScript is a preferred programming language for the front end of web app development. For that reason, TypeScript may be used for the same reason, but it also works well on the server side for complicated and large-scale enterprise projects.

Can TypeScript replace JavaScript?

No, TypeScript cannot be replaced with JavaScript. TypeScript is not suitable for almost all project types. JavaScript is a great choice when flexibility is a priority, whereas, TypeScript is the best option if you want to deal with large and complex projects.

Hardik Thakker

Hardik Thakker is a Co-Founder & CEO at Albiorix Technology. Having more than 10+ years of experience in handling the development team at a pace, he is totally involved in managing the overall aspects of the full-stack development processes. He completely believes in following Agile methodology and maintaining source code at the highest level of quality efficiency.

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