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17 Apr, 2024 | Mobile App Development

TypeScript vs JavaScript: Which One is Better to Choose?

TypeScript vs JavaScript: Which One is Better to Choose?

Introduction

TypeScript and JavaScript are two of the most popular programming languages for building client-side applications on the web. Both share syntax similarities but differ in fundamental aspects, like static vs. dynamic typing. JavaScript has been around since 1995 and is natively supported in all modern browsers. It is an essential part of the web and powers client-side logic through scripts. Its dynamic nature allows flexibility but lacks compiler checks. TypeScript was developed by Microsoft in 2010 as a typed superset of JavaScript, adding static typing and tooling support while still compiling to plain JavaScript. It aims to apply rigorous checking during development for fewer bugs. Since then, TypeScript has grown rapidly due to its promise of enhanced developer productivity and code quality. However, a pure replacement of JavaScript is not feasible given its ubiquity. This has led to diverse opinions on whether to choose TypeScript or JavaScript for a new project. This blog analyzes the core differences between TypeScript and JavaScript regarding their type systems, tooling, performance, and ecosystem to help understand their strengths and whether one is a better choice in different scenarios. It also addresses common questions developers face when deciding which language to adopt. TypeScript and JavaScript contact to know more

What is TypeScript?

TypeScript is an open-source programming language developed and maintained by Microsoft. It is a strict syntactical superset of JavaScript and primarily adds optional static typing to the language.  This helps catch errors early and allows leveraging modern tooling. Today, 55,944+ websites are using this effective language worldwide. TypeScript compilation outputs plain JavaScript code, allowing it to run directly in any web browser or JavaScript runtime environment. It builds on JavaScript syntax and provides features like classes, interfaces, typed variables, and error checking during compilation. This superior type-safety and IntelliSense capabilities aid in managing large codebases. The codebases are also highly scalable and reusable. Its static analysis at compile time means programmers can build robust apps with more maintainable code.  With increased adoption by enterprises, TypeScript promises longevity and acts as the safe evolution of JavaScript. It has secured its place in the industry with continued enhancements.

What is JavaScript?

JavaScript is a lightweight, cross-platform, and interpreted scripting language best known as the scripting language for Web pages. It was spearheaded by Netscape in 1995 and has since become essential for adding interactivity to Web pages. JavaScript can update dynamic HTML/XML content, control program flow, and handle events. It has made front-end development easier by enabling dynamic content reloading without reloading the web page.  JS also forms the basis of frontend frameworks like AngularJS and ReactJS for enhanced productivity. JavaScript is used by 98.7% (or 49,501.698 websites) of the websites worldwide. While JS excels at enabling interactive UIs and websites, its weakly typed and loosely structured nature initially made codebases hard to scale. However, features like classes, modules, and type-checking have advanced it significantly. Still evolving rapidly with improvements, JS remains the primary language for browser-based scripting.

Core differences between TypeScript and JavaScript

Now, we are in the post's primary section, where we will emphasize "Typescript vs JavaScript” in terms of different aspects. Let’s start!  

1. Static Typing

Static typing refers to a type system where the data type is known at compile time rather than run time. This means the compiler can validate and ensure the code uses the expected types correctly. Differences between TypeScript and Javascript according to Static Typing

TypeScript

JavaScript

TypeScript uses static typing where data types are known at compile time.

JavaScript uses dynamic typing where data types are checked at run time only.

The benefits of static typing include catching errors early during compilation, providing auto-complete suggestions in editors, and refactoring code safely.

No type-checking is done during compilation. Any type of error is caught during execution.

Benefits of static typing in TypeScript:
  • Catch errors early: Static type checking during compilation catches errors related to types, like passing wrongly typed parameters to functions. This helps fix issues early.
  • Auto-complete: Editor suggestions are available based on static types, improving developer productivity.
  • Refactoring: Refactoring code is safer as the compiler catches any introduced type errors.
  • Documentation: Types provide documentation for parameters/return values useful during collaboration.
JavaScript is dynamically typed:
  • No type-checking was done during compilation. Code is only checked at runtime.
  • No errors were caught during the writing/editing of code related to types. Only surfaces during execution.
  • No auto-complete suggestions related to types in code editors.
  • Refactoring carries the risk of introducing hidden type bugs not caught until runtime.
  • Missing documentation for functions regarding expected/return types.

2. Compile-time Checks

TypeScript code is compiled to JavaScript, allowing static analysis that catches errors before runtime. This improves productivity by fixing bugs sooner. Features like refactoring are also safer in TypeScript. JavaScript, on the other hand, does not have this compile-time safety net. Differences between TypeScript and Javascript according to Compile-time Checks

Aspect

TypeScript

JavaScript

Compilation

Type checks and errors are shown

No compilation - Runs directly

Benefits

Fix errors early, and refactors is safe

Errors only at runtime

TypeScript compilation process:
  • TypeScript code is first compiled into JavaScript code.
  • During compilation, the type checker validates types across the codebase.
  • Any type errors, missing imports, etc, are reported at compile time before runtime.
Benefits of compile-time checks:
  • Catches errors early before running code
  • Fix and prevent bugs before they occur at runtime
  • Enables refactoring safely by catching issues during compile
  • Improves code quality by validating correct usage of types
No compile-time checks in JavaScript:
  • JavaScript code executes directly without the compilation step
  • No type checking or validation of code done beforehand
  • Errors related to types only occur and are reported at runtime
  • No guarantee code is bug-free before executing

3. Interfaces

Interfaces in TypeScript define contracts for objects and functions to implement. This allows for describing relationships between various components. Interfaces promote code reuse through strong abstraction and decoupling of types from implementations. This aids in developing robust and maintainable apps over JavaScript's looser implicit typing. Differences between TypeScript and Javascript according to Interfaces

TypeScript

JavaScript

Has support for primitive types like numbers, strings, booleans, etc, and composite types like arrays, objects, tuples, enums, unions, voids, etc.

Similar primitive types as TypeScript but no other composite types.

Type aliases and interfaces can be created for reusable custom types.

No custom types support, relies on native types.

Benefits of TypeScript interfaces:
  • Enforce contracts between classes/functions
  • Self-documenting code with interfaces
  • Strict type-checking for objects
  • Aids refactoring by catching failures to adhere to shape
JavaScript does not have interfaces:
  • No way to define custom value shapes that classes/functions can adhere to
  • Missing type safety between functions/classes interacting with each other
  • Harder to understand expected object properties from code
  • Difficult refactoring if changing class structure

4. Object-Oriented Programming

OOP refers to programming using objects and related concepts like abstraction, encapsulation, polymorphism, and inheritance. It allows the modeling of real-world entities as objects that interact by passing messages.  Below are the features that we are going to assess in context to the comparison of TypeScript and JavaScript:
  • Classes - Classes are blueprints for objects that define their properties and behaviors. They support inheritance and polymorphism.
  • Encapsulation - It is the bundling of data with the methods that operate on that data. Encapsulation prevents data from direct modification.
  • Inheritance - It allows the creation of new classes that reuse and inherit properties and behaviors of existing classes.
  • Interfaces - Interfaces define common behaviors/actions but leave implementation to classes. It allows polymorphism.
  • Abstraction - It focuses on important attributes hiding unnecessary details behind class/interface definitions.
  • Polymorphism - It means multiple forms and allows one interface with multiple implementations through inheritance.
Differences between TypeScript and Javascript according to OOP

Feature

TypeScript

JavaScript

Classes

Supported with class keyword

Prototypal inheritance with constructor functions

Encapsulation

Access modifiers like public, private, protected

No access modifiers

Inheritance

Classes can be extended to other classes

Prototypal inheritance

Interfaces

Define common structures for classes to follow

No language-level interfaces

Abstraction

Abstract classes & interfaces

No language abstraction support

Polymorphism

Method overriding

Polymorphism via prototypal inheritance

Benefits of OOP in TypeScript:
  • Supports OOP concepts like classes, inheritance, and abstraction, allowing object-oriented modeling
  • Encapsulates state and behaviors within classes
  • Interfaces define common shapes for multiple classes
  • Inheritance allows code reuse through class extension
Limited OOP concepts in JavaScript:
  • Prototypal inheritance instead of classes
  • No access modifiers like private
  • Object models built via prototypes lack abstraction and structure
  • Functions mimic classes but miss OOP structure

5. Development Tools and IDE Support

Development tools refer to compilers, linters, editors, debuggers, etc, that improve developer productivity and code quality. Below are the attributes that differentiate both TypeScript and JavaScript. Check it out:
  • Auto Complete - It intelligently suggests properties and methods as code is typed based on static type analysis.
  • Refactoring Support - Refactoring is supported through rename/extract methods etc without breaking existing code.
  • Linting & Errors - Linting performs static analysis to find stylistic/structural errors, while errors highlight issues.
  • Debugging - Debugging tools allow stepping through code, inspecting scope, accessing variable values etc.
  • Code Navigation - It allows quickly navigating to references, traversing hierarchical imports, file structures etc.
Check out the development tools and IDE support available in TypeScript vs JavaScript:

Feature

TypeScript

JavaScript

Auto Complete

Supported based on static types

No auto-complete of types

Refactoring Support

Supported with type-checking

Limited due to lack of types

Linting & Errors

Supported by TSC compiler

Limited linting, errors at runtime

Debugging

Full source-level debugging

Limitations in debugging

Code Navigation

Go to definition, see callers supported

No static type aware navigation

Benefits of TypeScript IDE Features:
  • Autocomplete speeds up coding based on expected types
  • Refactoring safety via compilation checking for breaking changes
  • Bugs caught during editing via linting rather than runtime
  • Seamless debugging experience with source maps
JavaScript tooling has improved but is still inconsistent with TypeScript's static analysis abilities.

6. Application Performance

Performance refers to how fast an application executes and responds and efficient memory usage.  Here are a few app performance features that differentiate TypeScript and JavaScript. 
  • Type Check Overhead - Type checking during compilation increases bundle size and initialization time.
  • Bundle Size - Larger bundles require more bandwidth for loading applications.
  • Initialization - Initialization is the loading and execution of code during app startup.
  • Runtime - Runtime is the time taken for code execution after app initialization and loading.
Check out the Application performance considerations in TypeScript vs JavaScript:

Feature

TypeScript

JavaScript

Type Check Overhead

Types removed through  transpilation

No type-checking overhead

Bundle Size

Slightly larger due to type definitions

Smallest size without types

Initialization

Marginally slower with type checks

Fastest initialization

Runtime

Near identical performance

Potentially faster execution

Type erasure removes types after TypeScript compilation, keeping code size almost equivalent to JavaScript. Modern bundlers also minimize runtime overhead. In most cases, nominal performance differences are negligible compared to gains in developer productivity from TypeScript.

7. Backward Compatibility

Backward compatibility refers to the ability of newer versions of software to work with older versions.  Below are the features of Backward Compatibility that showcase the difference between TypeScript and JavaScript:
  • Compilation Target - Older JS versions for wider browser coverage without the latest JS features.
  • JavaScript Compatibility - Maintains compatibility while adding new language features.
  • Browser Support - Needs compilation for older browser support while JS runs directly.
  • Features Parity - Maintains language structure and semantics comparable to JavaScript.
Check out the Backward Compatibility in TypeScript vs JavaScript

Feature

TypeScript

JavaScript

Compilation Target

Compiled to plain JavaScript

Interpreted/JIT compiled

JavaScript Compatibility

Can use any JavaScript library

Natively compatible

Browser Support

Requires transpilation for browser support

Runs natively in browsers

Features Parity

Occasional missing features vs latest JS

Keeps full parity

TypeScript compiles to plain JavaScript, allowing the use of any existing JavaScript libraries and frameworks without issues. New TypeScript versions don't break existing code and stay backward compatible. JavaScript has remained backward compatible by design - newer scripts can run in older JavaScript environments. Features are added without breaking changes to existing codebases.

8. Modern JavaScript Support

Keeping pace with the latest advances in JavaScript language and ecosystem, we have identified 3 features to compare TypeScript and Javascript.  Here are these 3 features:
  • Latest ECMAScript: A standard programming language used for client-side scripting on the World Wide Web. 
  • Types Checking: A feature that checks your program is correctly coded before execution. There are 2 types of Type checking - Static and Dynamic. 
  • Transpiling for Older Browsers: A feature to convert a language’s source code into an equivalent version of the same or different programming language. 
In the table below, we have represented how these features are used in the exosystem of TypeScript and JavaScript Check out the differences between TypeScript and JavaScript in the context of Modern JavaScript Support:

Feature

TypeScript

JavaScript

Latest ECMAScript Features

Supported via TypeScript versions

Support varies across environments

Type Checking for New Features

Yes, provides types for all features

No type of safety for new APIs

Transpiling for Older Browsers

Compiles to ES5 for browser compat

Needs transpilation for older browsers

Future-Proof Code

Leverage upcoming features now

Need to wait for native support

TypeScript adds typed support for new JavaScript features as they emerge, enabling their use immediately. JavaScript must wait for native implementation across runtimes.

9. Learning Curve

It means the amount of initial effort that is required to learn the language. Below we discuss differences of the same in terms of TypeScript and JavaScript. Check out the Learning Curve differences for TypeScript vs JavaScript:

Aspect

TypeScript

JavaScript

Static Typing Concepts

Must learn static typing paradigm

No prior static typing is needed

Code Editing

Robust IDE with types improves DX

Limited DX without types initially

OOP Concepts

To understand classes and interfaces

To learn Prototypal patterns

Ramp-Up Time

More effort than JavaScript

Easy to pick up dynamically typed code

Long Term Benefits

Outweighs the initial learning time

Flexible but lack of type safety

While TypeScript has a larger initial learning curve, its benefits, such as safety and productivity, far outweigh the costs over the long term. Both languages can coexist and learn together.

10. Maturity and Adoption

When it comes to maturity and adoption, it is considered to be different phases or stages of development and community support levels. Below, we discuss different parameters of development stages that differentiate TypeScript and JavaScript. Check out the Maturity differences in TypeScript vs. JavaScript:

Parameter

TypeScript

JavaScript

Age

Introduced in 2012

Existed since 1995

Adoption Growth

Growing exponentially

Almost universal

Framework Support

Excellent compatibility

Prototypical inheritance

Language Specification

ECMA standard approved in 2020

ECMA-262standard

Community Support

Very active on GitHub, Stack Overflow

One of the largest communities

Future Roadmap

Actively developed by Microsoft

Maintained by TC39 committee

While JavaScript has decades of head start in terms of maturity, TypeScript adoption is growing rapidly among new projects due to strong developer experience and backing from Microsoft. Both have large communities and long-term prospects.

Should I learn JavaScript or TypeScript?

TypeScript builds on JavaScript syntax and adds optional static types, interfaces, and class features. Learning TypeScript is better for new projects because of its robust type safety and compiler checks, which reduce bugs.  However, JS still has excellent browser support and compatibility. Overall, it is better to learn both for a full-stack career.

Will TypeScript Replace JavaScript?

Considering JavaScript's dominance in web development, it is unlikely TypeScript will fully replace it. However, TypeScript is projected to become the mainstream language of choice for new complex web applications due to its strong typing, compiler capabilities and being a superset of JavaScript.  It ensures safer and more maintainable apps at scale. JavaScript will still be required for runtime compatibility but TypeScript will eventually overtake JS for new large projects for its advantages.

Final Verdict

So, TypeScript combines the debugging and catch-errors-early benefits of static typing with JavaScript's flexibility to significantly improve the development experience without major trade-offs in comprehension, compatibility, or performance.  For new applications, libraries, and frameworks, TypeScript is generally the best choice to write high-quality code while leveraging modern IDE features and tooling.  While JavaScript will remain relevant, TypeScript hits an excellent balance of type safety with approachability, making it the future-proof option. Make your choice wisely! Learn more about TypeScript vs JavaScript

Frequently Asked Questions

1. Is it ideal to learn TypeScript or JavaScript?

If you are just starting out, it's better to learn JavaScript first to understand core programming concepts. TypeScript builds on JavaScript, so learning JavaScript provides a strong foundation.  However, TypeScript isn't vastly more difficult - so it can also be learned directly, especially if wanting to work with types from the beginning.

2. Is Typescript better than JavaScript?

It's generally not recommended to replace an existing JavaScript codebase with TypeScript outright. TypeScript is highly compatible with JavaScript, so both can co-exist with TypeScript code being able to use JavaScript libraries and vice versa.  New projects are better started with TypeScript while existing codebases can migrate incrementally.

3. What is more in common, JS or TS?

JavaScript is by far the most popular and widely used language currently based on usage statistics. However, TypeScript adoption is growing rapidly among new projects for its type safety and tooling benefits.  Both have enormous communities and long-term prospects, so popularity depends on the use case and requirements.

4. Which is more relevant for React, JavaScript, or TypeScript?

TypeScript is a smarter choice for React projects because it supports static types across React components and libraries.  Although plain JavaScript works, too, TypeScript allows type-checking interactions between React components, propTypes, and states for fewer bugs. It also safely enables refactoring React apps and improves developer experience through rich editor features.  In summary, while JavaScript will continue to dominate due to its ubiquity, TypeScript has established itself as the preferred choice for new projects. It prioritizes developer productivity, stability, and performance through its strong static typing system. Both languages can coexist depending on an application's specific needs.

Pratik
Written by Pratik

Pratik is a co-founder of WEDOWEBAPPS LLC. He has been at the forefront of the business, expanding it globally with the latest technologies. He also has a passion for sharing his expertise with clients and other enthusiasts. He usually writes based on Technology, Leadership, and Entrepreneurship.

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