Typescript basics

 1. What is TypeScript?

Think of TypeScript as an improved version of JavaScript. It helps developers write better and more reliable code by adding a feature called "static typing," which means we can specify the types of values in our code.

Example:

// JavaScript code 
function add(x, y) 
{ return x + y; } 
// TypeScript code with type annotations 
function add(x: number, y: number): number 
{ return x + y; } 

2. Setting Up TypeScript

To use TypeScript, we need to install it on our computer. We can do this by running a simple command. Once installed, write the code in files with a .ts extension and then use a tool to convert it into regular JavaScript.

Example:

# Install TypeScript globally npm install -g typescript 
# Create a TypeScript file (e.g., yourfile.ts) 
# Compile it into JavaScript using the tsc command tsc yourfile.ts 

3. Type Annotations and Inference

In TypeScript, we can say what type (like a number or text) a variable should be. For example, if we have a variable storing an age, we can explicitly say it's a number. TypeScript can also figure out the types on its own in many cases.

Example:

// Type annotations 
let age: number =25;
let name: string = "John"; 
// Type inference 
let isAdmin = false; 
// TypeScript knows this is a boolean 

4. Interfaces

Interfaces are like rules for how an object should look. If we say an object should have a name and an age, TypeScript makes sure us follow these rules when creating or using that object.

Example:

// Interface defining the structure of a person interface Person { name: string; age: number; } 
// Using the interface to create an object let user: Person = { name: "Alice", age: 30, }; 

5.Enums

Enums help us define a set of names for things. For instance, if we're working with colors, we can create an enum with names like Red, Green, and Blue, making your code more readable.

Example:

// Enum defining colors
enum Color { Red, Green, Blue, } 
// Using the enum 
let myColor: Color = Color.Green; 

These examples should provide a practical understanding of how TypeScript works and how it can improve the development process.