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TypeScript vs JavaScript Syntax Differences: Learn Key Insights Now

Find the typescript vs javascript syntax differences, Similarities between the both, and how to choose between them.

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    JavaScript and TypeScript. It’s very likely you’ve heard either or both of these words before, if you are a website designer or a person acquainted with programming in general. However, if we look at TypeScript vs JavaScript popularity, we will find that JavaScript may be a more popular word for developers that they have always come across, but not TypeScript, so what is typescript vs javascript syntax differences.

    We will discuss typescript vs javascript syntax differences and the features of these languages including performance, ecosystem, developer experience and tooling in this article. We will also highlight the differences between them and try to see what they share. After reading this guide, you will have enough knowledge about typescript vs javascript syntax differences and how to choose whether you want to use Typescript or Javascript in your next project in addition to typescript vs javascript syntax differences.

    TypeScript vs JavaScript Examples

    You might have asked why the two terms look so similar and probably thought that they were the same only that their spelling differed. Nevertheless, there are typescript vs javascript syntax differences as they are different programming languages which exhibit distinct features; there are some similarities between them. We will discuss the definitions of both with examples and the functions of both:

    What Is JavaScript language?

    JS is a high-level scripting language for web applications used to create dynamic, interactive content. JavaScript is one of the core technologies in use today for developing modern web applications among them being HTML and CSS.

    JavaScript is highly readable, which is one of its most loved features. The example code below demonstrates a simple JavaScript function that calculates the Fibonacci Series up to a given number:

    Example of JavaScript function

    function calculateSum(num1, num2) {

      return num1 + num2;


    // Usage

    const result = calculateSum(5, 3);

    console.log(result); // Output: 8

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    Major Features of JavaScript

    Java script has some features that make it different from other programming languages such as TypeScript, that include:

    • Weak and Dynamically Typed, JavaScript is sometimes referred to as a weakly typed language due to the fact that there are instances where types can be converted implicitly depending on how they are being used. This has made programming in JavaScript more user-friendly but has also been faulted for causing unexpected outcomes and defects in many JavaScript programs.
    • Multi-Paradigm Language, JavaScript also supports many other different programming paradigms. This advantage is that it lets developers pick up the most fitting style of coding (i.e., organizing) for their own purposes.
    • Just-in-Time Compilation, JavaScript runtime environments use this technique of just-in-time compilation for enhancing execution efficiency.
    • Prototype-Based Object Orientation, JavaScript is different from other languages such as Python and Java based on its prototype inheritance model for object-oriented programming.
    • Asynchronous Programming, No other programming language can provide the benefit of handling asynchrony for jobs independent of the main program flow and how such events are supposed to be managed.
    • Versatile, This is one of the most loved features of JavaScript and a reason why it is so widely used. Variability of JavaScript’s usage could be seen in several key areas like mobile app building, game creation, artificial intelligence (which applies tools such as Tensorflow.js), Internet of Things and many other areas.

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    What is typescript?

    TypeScript (TS) is an object-oriented programming language that builds on JavaScript using a class-based approach. TypeScript is designed as a superset of JavaScript, so that any valid TypeScript code is also valid JavaScript code in the end. TypeScript enables optional type annotations to be added to JavaScript which allow type checking during compile time and help catch errors early in the development process.

    Example of TypeScript function

    function calculateSum(num1: number, num2: number): number {

      return num1 + num2;}

    // Usage

    const result: number = calculateSum(5, 3);

    console.log(result); // Output: 8

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    Features of TypeScript

    If you watched any TypeScript tutorial, you will notice that all the features of JavaScript are included automatically. TypeScript has some other aspects not available in JavaScript that make it better, which include:

    • Strongly and Statically Typed, The distinguishing feature of TypeScript from JavaScript is that it can include type checking and certifying the type correctness of your application code at compile time. In this way, it detects and corrects mistakes as they happen before execution so you can release codes to production with more assurance.
    • Type Inference, TypeScript’s superpowers don’t end at the ability to detect the type of a variable or function return type even when one doesn’t explicitly specify the type itself. TypeScript can determine the type of a variable automatically based on its initialization value and how it is used in your code.
    • Compile-Time Error Checking, TypeScript’s static type checking is performed during the compilation stage, which is before execution and it checks for errors in your code. It performs a scan of your program and imposes hardened type-checking regulations towards the runtime of your code to squeeze out possible bugs.
    • Enumerated Types, TypeScript also supports enumerated types that are also referred to as enums in some programming languages.

    know that you know the features of both languages, you need to know the similarities before you know the typescript vs javascript syntax differences.

    Similarities Between TypeScript and JavaScript

    Before discussing TypeScript vs JavaScript Syntax Differences we shall critically consider the shared commonalities of JavaScript and TypeScript:

    • Declaring a Variable in TypeScrip, Web Development and Server-Side Programming: As a result, both languages perform the same function but you should also remember that whatever JavaScript can do, TypeScript can do better.
    • ECMAScript Compatibility, As TypeScript is developed to be a superset of JavaScript and JavaScript follows ECMAScript standards, these principles are automatically applied to TypeScript as well. This similarity allows TypeScript to remain interoperable with the JavaScript ecosystem.
    • Support for the Same Libraries and Frameworks, Additionally, any project built in JavaScript can be converted to use Typescript while maintaining those libraries or frameworks that were used initially in such projects. The ease of migration from one language to another makes it convenient to gradually introduce Typescript into your projects built on Javascript.
    • Execution Environment, Moreover, these two languages can run in similar runtime environments. Besides, JavaScript depends on a runtime environment like web browser or node.js. Likewise, for all its code transpiled into Java Script code at the end of every translation; this implies the same for typescript too.
    • Common Development Tools, Again, another similarity between JavaScript and TypeScript is that they have shared development tools such as code editors, debuggers, package managers in Yarn for example and build tools like Webpack.

    Now lets discuss typescript vs javascript syntax differences in details.

    TypeScript vs JavaScript syntax differences

    The syntax of JavaScript and TypeScript is almost the same, but the TypeScript syntax has a few differences. Basically, through TypeScript, you will always be able to write your code in such a way that it can work as you had originally intended without having any ambiguity unlike JavaScript which is a dynamically typed language.

    TypeScript introduces additional syntax and features on top of JavaScript to provide static typing and other compile-time checks. Here are some of typescript vs javascript syntax differences:

    Variable Declarations

    • JavaScript: Variables can be declared using the var, let, or const keywords.
    • TypeScript: Same as JavaScript, but TypeScript also supports type annotations for variables.

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    Type Annotations

    • JavaScript: Variables do not have explicit type annotations.
    • TypeScript: Variables can have explicit type annotations. 

    Type Inference

    • JavaScript: The type of a variable is determined dynamically at runtime based on the assigned value.
    • TypeScript: TypeScript’s static type system allows type inference, where the type of a variable is determined by the TypeScript compiler based on the assigned value.

    Function Declarations

    • JavaScript: Functions can be declared using the function keyword.
    • TypeScript: Same as JavaScript, but TypeScript also supports type annotations for function parameters and return types.

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    Interfaces and Types

    • JavaScript: Does not have built-in support for interfaces or type definitions.
    • TypeScript: Supports interfaces and type definitions, which allow you to define the shape of objects or create custom types.


    • JavaScript: Does not have a dedicated syntax for enumerations.
    • TypeScript: Supports enumerations, which allow you to define a set of named values.


    • JavaScript: Supports object-oriented programming with the class keyword introduced in ECMAScript 2015 (ES6).
    • TypeScript: Same as JavaScript, but TypeScript also supports access modifiers (public, private, protected), inheritance, and interfaces for classes.

    Modules and Namespaces:

    • JavaScript: Supports modules using the import and export keywords, introduced in ES6.
    • TypeScript: Same as JavaScript, but TypeScript also supports additional module formats and provides support for namespaces.

    But if we look at TypeScript vs JavaScript performance, we will find that there is no difference but TypeScript may be a little better for writing clean codes.

    General typescript vs javascript differences

    There exists numerous areas where JavaScript differs from TypeScript. Below are some of the differences that you ought to know:

    • Transpiled language: JavaScript before running time changes your code into Javascript by using the TypeScript Compiler (TC) 
    • Learning curve: JavaScript has a less steep learning curve compared to TypeScript. You need to comprehend basic programming concepts and syntax in addition to javascript specific features and browser compatibility.
    • Developer experience: With its dynamic development environment and loose typing,JavaScript offers a flexible developer experience that allows for rapid prototyping as well as easy integration with different frameworks and libraries.

    Additionally, better tooling results in an enhanced developer experience for TypeScript users through; improved code editor support, static typing; therefore facilitating better code maintainability, refactoring ability and early detection of potential errors.

    Should I learn TypeScript or JavaScript?

    This question does not have a straightforward answer. But if you’ve been reading this article from the beginning, you should know by now that your answer to this question is going to depend on other factors and yourself. Think about the following things so that you can make informed judgments on your use case:

    • Project Requirements and Scalability, The project requirements for which you are working on will determine whether to go for JavaScript or TypeScript. For instance, if it is an open-source product with numerous collaborators, then TypeScript could be preferable over JavaScript. 
    • Your Expertise and Preferences, A project involving TypeScript needs a lot of commitment, such as having the knowledge needed to comprehend several concepts such as generics, namespaces, utility types alongside other TypeScript-specific concepts. 
    • Existing Codebase and Compatibility Considerations, Converting everything into TypeScript from JavaScript ,for instance,may take much time and many resources given that you have a huge codebase with most of the part written in Javascript
    • Small Projects or Quick Prototypes, If you’re working on a small project or trying out new tech, then an alternative can be JavaScript because of its low learning curve compared to the other languages.
    • Large-Scale or Enterprise-Level Applications, Nowadays, many enterprise applications are migrating their codebase from JavaScript to TypeScript because it provides many advantages including security, enhanced tooling and IDE support, and improved developer experience. Next time you are building a large-scale/enterprise application that deals with much sensitive user data, probably you should emulate these enterprises in using Typescript.


    There are two common terminologies that frequently occur in programming world i.e. JavaScript and Typescript hence it is important to comprehend the dissimilarities and capabilities of these two languages. However, the choice between the two depends on what has been discussed so far above before finally deciding which one suits your use case.

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