Typescript vs. JavaScript: A Comprehensive Comparison

JavaScript has received a lot of praise because of its powerful features to enhance website interaction. JavaScript is the most used scripting language for many web development projects and has been in existence for a while now.

TypeScript can be defined as a type of JavaScript with a set of additional features. In this article, we compare the two languages head-on.

Before considering their significant differences, let us first understand their features and their importance to your application.

JavaScript

A popular programming language in web development is object-oriented and lightweight in terms of memory and supports cross-platform development.

It is mostly used on the client-side of a dynamic web page. The JS code is called a script. The scripts are embedded within web pages and executed automatically when a web page loads.

The script runs as it is provided in simple text and does not need any special compilations. This feature makes JS relatively fast.

History of JavaScript

JavaScript language was initially called Moncha, and Brendan Eich of Netscape Communications Corporation launched it in September 1995.

In 1996, Netscape presented JavaScript to the European Computer Manufacturers Association (ECMA)  as the best scripting tool, which further supports Java in browsers.

Features of JavaScript

1. Low reloading speed

JS immediately references any changes made by developers to the client-side. Therefore, the developer will not have to wait too long.

2. Interaction

It gives the best user experience (UX) because an interface is created for a mouse hovering over an interface to produce a reaction.

3. Excellent for communication with a server

It gives an option for user input validation before sending the page to the server.

4. Date and Time functions

Customized messages can be sent to a user in any particular location, for example, greeting a user with their local time and date.

How to use JavaScript

Developers can use JavaScript within HTML pages in the following two ways:

Typescript

Just like JavaScript, Typescript is an open-source and object-oriented scripting language.

It is among the JavaScript supersets which can easily compile to JavaScript without a problem.

However, running TS on a browser is quite different. It should first be compiled to generate a JavaScript file that runs on the browser.

A Typescript file can run on any device and has a “.ts” extension.

History of Typescript

Microsoft developed Typescript and also maintained it under the Apache 2 license.

It was developed by a programmer called Andres Hejlsberg and introduced for use in October 2012.

In 2013, a new version of Typescript was developed by Microsoft- TypeScript  0.9.

The latest stable version is TypeScript 3.4.5, which was released in April 2019.

Features of Typescript

Knowing JavaScript is a prerequisite to learning Typescript. The elementary building blocks for code structure are inherited from JavaScript.

Since it is after JavaScript, running TypeScript code involves first converting it to JavaScript before execution.

1. Portable

Typescript can run on many environments just like JavaScript without encountering any problems on browsers.

Running a Typescript code does not need a defined run-time environment or a specific virtual machine for execution.

2. Transpiler

Transpiling is a Typescript feature that offers error-checking.

The developer can check the actual script for any errors by just running it on a compiler.

3. Type checking

Static type-checking is expected in Typescript, which is done during compile time. The errors are easily observed while typing the code, so there is no need to wait till execution before making changes while you can see them.

4. DOM management

Typescript can be useful in adding and removing elements in DOM.

How to use Typescript

Files containing a typescript code end with the extension “.ts.”

Typescript allows a programmer to write the code in a simple editor such as notepad before converting it into Javascript. It is then included in the HTML source code to be run on any browser.

So far, we have looked at the definitions and features of both scripting languages. Let us now make a comparison to find out how they are unique from each other.

Critical differences between JavaScript and TypeScript

Let us make a descriptive comparison based on different factors:

1. Type

TypeScript: An object-oriented compile language with powerful features

JavaScript: high level interpreted programming language

2. Design and Development

TypeScript: founded by Anders Hejlsberg, a programmer at Microsoft

JavaScript: founded by Brendan Eich of Netscape Communications Corporation, ECMA International

3. Lightweight/heavyweight

TypeScript: A very lightweight interpreted coding language

JavaScript: A bit heavier than Typescript and designed for developing enterprise applications

4. Server / Client side

TypeScript: Deployed on client-side only

JavaScript: deployed on both client and server-side

5. File extension

TypeScript: .ts, .tsx

JavaScript: .js

6. Syntax

The syntax is a set of standard rules for structuring code in different languages where each specifies its bits of syntax.

TypeScript: comprises variables, statements, expressions, functions, and modules

JavaScript: Every statement is written inside a script tag, which requests the client to execute all content between the tags.

<script>
//your code here
</script>

7. Annotations

TypeScript: to get the most out of its features, TypeScript code must be annotated continuously by the developer.

JavaScript: annotations are not necessary for JavaScript code

8. Time for Compiling

TypeScript: code compilation takes time

JavaScript: code compilation is faster

9. Interface

TypeScript: Its interface allows connections with applications

JavaScript: No interface for connecting with other application

JavaScript allows developers to make web pages as interactive as possible, while Typescript is a form of JavaScript with additional features.

Typescript allows prototyping to explore new concepts, while JavaScript does not have this feature.

When should you use either of the Languages?

Typescript

1. when compile-time type checking is preferred.

Vanilla JavaScript makes it possible to do runtime verification. This process, however, introduces run-time overheads. We use compile-time validation to avoid them.

2. When you have just started to code using a new library or framework

Assuming you have chosen React for your new project and therefore not wholly familiar with React’s API, you can use IntelliSense, which is a type definition they offer to help you navigate and discover new interfaces.

3. collaborating on significant projects with other developers

When several developers are collaborating on a single project, Typescript makes sense. It becomes invaluable when different APIs can communicate using Typescript’s interfaces and access modifiers.

JavaScript

1. Build tools required

It has become almost impossible to develop JavaScript applications without building tools, unlike Typescript, which requires a build step before producing the final JavaScript for execution.

2. Small projects

JavaScript is the most suitable for small projects with a small code surface area.

3. Strong testing workflow

It might be like taking a risk to switch to Typescript if you have a dependable JavaScript team already implementing test-driven development.

4. Added dependencies

TS requires you to have their type definitions for you to use their libraries. An extra type definition means an extra npm package. Using extra packages means that you know the risks associated with incorrect or unmaintained packages.

Choosing not to import the type definitions means missing much of the Typescript benefits. However, typed projects do exist to mitigate such risks. A popular library indicates a higher probability of being maintained for more extended periods into the future.

5. Unsupported framework

Using a framework that does not support TS, for example, EmberJS limits you, and you miss out on the benefits of using TS.

JavaScript vs. TypeScript: head to head comparison

JavaScript	TypeScript
A scripting language for developing dynamic web pages	A JavaScript superset for tackling large code projects through collaboration
In interpreted languages, therefore, it is possible to find errors during run time.	Errors can be discovered and corrected during compilations
No option for static typing weakly typed	Supports both static and dynamic typing, strongly typed
Used directly on browsers	Converted into JavaScript before use on browsers
JS libraries work by default	All JS libraries and code works without any changes since its a superset
Does not support compilation of any of the ES features	TS supports all ES features
It does not support modules, generics, and interfaces	Supports module, generics, and interface for data definition
The feature for functions to have optional parameters is not available	Functions can have optional parameters
Example code:function sum (x, y) {  return x+y;}var result = sum(20, 35);console.log(`adding x and y we get ` + result);	Example code:<script>function sum (x:number, y:number) :number {  return x+y;}var result = sum(25,35);document.write (`adding x and y we get ` + result);</script>
Numbers and strings are classified as objects	Numbers and strings are considered to be interfaces
It mostly suits simple web applications because of its neat and clean structure	A powerful and intuitive language
Backed up by huge community support around the globe with many documentations and supports finding solutions to issues	The community around this language is not so huge and still expanding
It does not support creating prototypes	Supports forming prototypes
No primary scripting language is needed and can be learned right on the go!	Scripting knowledge is a prerequisite and takes time to learn how to code
It does not require a build setup.	Requires a proper build setup for defining static types

JavaScript or TypeScript? Which is Better?

We can say that JavaScript highly suits relatively small coding projects. For large projects that need collaboration and teamwork, Typescript would be the most preferred alternative.

Take note of this:

Assume you have decided to introduce a type system to the front-end web development workflow.

Typescript won’t be the only option. Facebook’s Flow and Google’s Closure are the two significant types of annotation tools worth considering.

Concluding Remarks

All said and done, either language has its features, benefits, and limits. JS is lightweight and used for creating dynamic HTML web pages. It is, however, not a fully-fledged programming language. It comes inside a web browser since it is an interpreted language.

Typescript is compiled to JavaScript; therefore, it can be employed for JavaScript codes, making it more popular and commonplace. With each subsequent Typescript release, newer and improved features make it excellent for any experienced developer.

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