Major Differences Between TypeScript and JavaScript: 5 Key Points with Simple Code Examples
JavaScript and TypeScript are two of the most popular programming languages for web development. While JavaScript has been around for many years and is widely used, TypeScript is a more recent addition that brings additional features to JavaScript. In this blog post, we'll explore 10 key differences between JavaScript and TypeScript, providing simple code examples to help you understand their differences clearly. 1. The Type System JavaScript is dynamically typed, meaning variables can hold any type of data and change types on the fly. In TypeScript, you get static typing, meaning you define the types of your variables upfront. This helps catch errors early and makes your code safer. let name = "John"; name = 10; // This works fine in JavaScript let name: string = "John"; name = 10; // TypeScript will throw an error because 10 is a number, not a string 2. Compilation JavaScript runs directly in the browser or Node.js without any need for a build step. However, TypeScript needs to be compiled into JavaScript before it runs in the browser or Node.js. It’s like TypeScript gets translated into something your environment understands. tsc app.ts // This compiles TypeScript code into JavaScript 3. Interfaces and Types JavaScript doesn’t support interfaces or custom types. TypeScript, on the other hand, allows you to define custom types and interfaces to ensure your data structures are used correctly. let person = { name: "John", age: 30 }; interface Person { name: string; age: number; } let person: Person = { name: "John", age: 30 }; // TypeScript ensures the object matches the interface 4. Type Inference JavaScript doesn’t infer types, so you manually track what type a variable holds. TypeScript automatically infers the type of variables based on their initial value, making your life easier. let num = 10; // You have to manually track that it's a number let num = 10; // TypeScript infers that 'num' is a number 5. Classes and Inheritance JavaScript supports classes and inheritance, but it’s fairly basic. TypeScript extends JavaScript’s class system by adding features like access modifiers (public, private, protected), making your code more flexible and maintainable. class Animal { constructor(name) { this.name = name; } } class Animal { public name: string; constructor(name: string) { this.name = name; } } Conclusion Both JavaScript and TypeScript have their strengths, but TypeScript provides more robust tooling, better type safety, and features that help manage larger projects. JavaScript will always be essential for web development, but if you’re working on a large-scale application or want to catch errors early, TypeScript might be the better choice. I hope this clears up the main differences between the two! Let me know if you’ve got any questions or need further explanation. Happy coding!
JavaScript and TypeScript are two of the most popular programming languages for web development. While JavaScript has been around for many years and is widely used, TypeScript is a more recent addition that brings additional features to JavaScript. In this blog post, we'll explore 10 key differences between JavaScript and TypeScript, providing simple code examples to help you understand their differences clearly.
1. The Type System
JavaScript is dynamically typed, meaning variables can hold any type of data and change types on the fly.
In TypeScript, you get static typing, meaning you define the types of your variables upfront. This helps catch errors early and makes your code safer.
let name = "John";
name = 10; // This works fine in JavaScript
let name: string = "John";
name = 10; // TypeScript will throw an error because 10 is a number, not a string
2. Compilation
JavaScript runs directly in the browser or Node.js without any need for a build step.
However, TypeScript needs to be compiled into JavaScript before it runs in the browser or Node.js. It’s like TypeScript gets translated into something your environment understands.
tsc app.ts // This compiles TypeScript code into JavaScript
3. Interfaces and Types
JavaScript doesn’t support interfaces or custom types.
TypeScript, on the other hand, allows you to define custom types and interfaces to ensure your data structures are used correctly.
let person = { name: "John", age: 30 };
interface Person {
name: string;
age: number;
}
let person: Person = { name: "John", age: 30 }; // TypeScript ensures the object matches the interface
4. Type Inference
JavaScript doesn’t infer types, so you manually track what type a variable holds.
TypeScript automatically infers the type of variables based on their initial value, making your life easier.
let num = 10; // You have to manually track that it's a number
let num = 10; // TypeScript infers that 'num' is a number
5. Classes and Inheritance
JavaScript supports classes and inheritance, but it’s fairly basic.
TypeScript extends JavaScript’s class system by adding features like access modifiers (public, private, protected), making your code more flexible and maintainable.
class Animal {
constructor(name) {
this.name = name;
}
}
class Animal {
public name: string;
constructor(name: string) {
this.name = name;
}
}
Conclusion
Both JavaScript and TypeScript have their strengths, but TypeScript provides more robust tooling, better type safety, and features that help manage larger projects. JavaScript will always be essential for web development, but if you’re working on a large-scale application or want to catch errors early, TypeScript might be the better choice.
I hope this clears up the main differences between the two! Let me know if you’ve got any questions or need further explanation. Happy coding!
