JavaScript ES6 vs TypeScript: A Comprehensive Comparison

JavaScript has been the backbone of web development for decades. With the release of ECMAScript 6 (ES6), JavaScript received a significant upgrade, introducing new features that made the language more powerful and developer - friendly. On the other hand, TypeScript, developed by Microsoft, is a superset of JavaScript that adds static typing to the language. In this blog, we'll compare JavaScript ES6 and TypeScript, exploring their fundamental concepts, usage methods, common practices, and best practices.

Table of Contents#

  1. Fundamental Concepts
  2. Usage Methods
  3. Common Practices
  4. Best Practices
  5. Conclusion
  6. References

Fundamental Concepts#

JavaScript ES6#

JavaScript ES6, also known as ECMAScript 2015, is a major version of the JavaScript language standard. It introduced many new features such as arrow functions, classes, let and const declarations, template literals, destructuring, and more. These features make JavaScript more concise and expressive.

Key Features:

  • Arrow Functions: A more concise way to write functions.
// Traditional function
function add(a, b) {
    return a + b;
}
 
// Arrow function
const addArrow = (a, b) => a + b;
  • Classes: A syntactic sugar for prototype - based inheritance.
class Person {
    constructor(name) {
        this.name = name;
    }
    greet() {
        console.log(`Hello, my name is ${this.name}`);
    }
}
  • let and const: let allows block - scoped variable declarations, and const is used for constants.
let variable = 'This is a let variable';
const constant = 'This is a constant';

TypeScript#

TypeScript is a statically typed superset of JavaScript. It adds a type system to JavaScript, which helps catch errors during development rather than at runtime. TypeScript code needs to be transpiled into plain JavaScript code before it can be run in a browser or Node.js environment.

Key Features:

  • Type Annotations: You can explicitly define the types of variables, function parameters, and return values.
function add(a: number, b: number): number {
    return a + b;
}
  • Interfaces: Interfaces define a contract that an object must follow.
interface Person {
    name: string;
    age: number;
}
 
const person: Person = { name: 'John', age: 30 };

Usage Methods#

JavaScript ES6#

JavaScript ES6 code can be run directly in modern browsers or Node.js without any additional compilation steps.

Running in the browser:

<!DOCTYPE html>
<html lang="en">
 
<head>
    <meta charset="UTF - 8">
</head>
 
<body>
    <script type="text/javascript">
        // ES6 code
        const message = 'Hello, ES6!';
        console.log(message);
    </script>
</body>
 
</html>

Running in Node.js: Create a file named es6Example.js with the following content:

const message = 'Hello, ES6 in Node.js!';
console.log(message);

Then run it using the command node es6Example.js

TypeScript#

TypeScript code needs to be transpiled into JavaScript. First, you need to install the TypeScript compiler globally using npm:

npm install -g typescript

Create a tsconfig.json file in your project root directory to configure the TypeScript compiler. A basic tsconfig.json might look like this:

{
    "compilerOptions": {
        "target": "ES6",
        "module": "commonjs",
        "outDir": "./dist"
    }
}

Create a TypeScript file, for example, typescriptExample.ts:

const message: string = 'Hello, TypeScript!';
console.log(message);

To transpile the TypeScript code, run the following command:

tsc typescriptExample.ts

This will generate a typescriptExample.js file in the dist directory (as configured in tsconfig.json). Then you can run the JavaScript file using Node.js:

node dist/typescriptExample.js

Common Practices#

JavaScript ES6#

  • Module Import/Export: ES6 introduced a standard way to import and export modules.
// math.js
export function add(a, b) {
    return a + b;
}
 
// main.js
import { add } from './math.js';
console.log(add(2, 3));
  • Destructuring: It simplifies extracting values from arrays or objects.
const person = { name: 'John', age: 30 };
const { name, age } = person;
console.log(name, age);

TypeScript#

  • Using Generics: Generics allow you to create reusable components that can work with different types.
function identity<T>(arg: T): T {
    return arg;
}
 
let output1 = identity<string>("myString");
let output2 = identity<number>(100);
  • Type Guards: Type guards help narrow down the type within a conditional block.
function printValue(value: string | number) {
    if (typeof value === 'string') {
        console.log(value.toUpperCase());
    } else {
        console.log(value.toFixed(2));
    }
}

Best Practices#

JavaScript ES6#

  • Use const by default: Whenever possible, use const to declare variables. This helps prevent accidental reassignment and makes the code more predictable.
const numbers = [1, 2, 3];
  • Leverage arrow functions for simple operations: Arrow functions are concise and have a more intuitive this binding.
const double = (num) => num * 2;

TypeScript#

  • Use strict mode: Enable strict mode in tsconfig.json ("strict": true). This enforces strong type checking and helps catch more errors during development.
{
    "compilerOptions": {
        "strict": true
    }
}
  • Separate concerns with interfaces and classes: Use interfaces to define the shape of objects and classes to implement the behavior.
interface Animal {
    name: string;
    makeSound(): void;
}
 
class Dog implements Animal {
    name: string;
    constructor(name: string) {
        this.name = name;
    }
    makeSound() {
        console.log('Woof!');
    }
}

Conclusion#

JavaScript ES6 and TypeScript each have their own strengths. JavaScript ES6 is a natural evolution of JavaScript, offering new features that make the language more modern and developer - friendly. It is easy to use and can be run directly without additional compilation steps in most modern environments.

On the other hand, TypeScript provides a static type system, which helps in catching errors early in the development process, making large - scale projects more maintainable.

If you are working on a small - scale project or need quick prototyping, JavaScript ES6 might be the better choice. For large - scale applications where code maintainability and error prevention are crucial, TypeScript is a more suitable option.

References#

2025-10