Difference between TypeScript and JavaScript

TypeScript and JavaScript are closely related, but they have key differences that make them suitable for different use cases:

1. Typing System

• JavaScript: Dynamic and loosely typed. Variables can hold any type of data, and types are determined at runtime. This flexibility can sometimes lead to errors.

let x = 5;   // x is a number
x = 'Hello'; // now x is a string

• TypeScript: Statically typed. You can define the types of variables, function parameters, and return values, which helps catch errors during development.

let x: number = 5;  // x is a number
x = 'Hello';        // Error: Type 'string' is not assignable to type 'number'

2. Compilation

• JavaScript: Interpreted language, run directly in browsers or Node.js without a compilation step.
• TypeScript: Compiled language that needs to be transpiled into JavaScript. The TypeScript compiler (TSC) converts TypeScript code into JavaScript that can be run in browsers or Node.js.

3. Features

• JavaScript: ES6+ introduces many modern features like classes, arrow functions, and promises. It is widely supported and used for both frontend and backend development.
• TypeScript: Offers all JavaScript features plus additional features like:
• Interfaces: Define the structure of objects.
• Generics: Write reusable code that works with different data types.
• Enums: Define a set of named constants.
• Access Modifiers: Control access to class members (public, private, protected).
• Decorators: Metadata annotations that can modify classes or methods.

4. Error Checking

• JavaScript: Errors are typically found at runtime, leading to potential issues during execution.
• TypeScript: Provides compile-time error checking, allowing developers to catch bugs earlier in the development process.

5. Development Environment Support

• JavaScript: Works out of the box in browsers and Node.js, and has a large ecosystem of tools, libraries, and frameworks.
• TypeScript: Requires setup (e.g., installing TypeScript compiler), but many modern development environments, like Visual Studio Code, have built-in TypeScript support with features like type checking, auto-completion, and refactoring tools.

6. Community and Adoption

• JavaScript: Vast community and ecosystem, with broad usage in web development.
• TypeScript: Growing rapidly, especially in large-scale projects, as it provides a more robust and maintainable way to manage large codebases.