JavaScript Lecture 1 Notes

Objective

• Start a series on JavaScript: from beginner to advanced level
• Prerequisite: No programming experience required
• Focus: Practical examples and projects along with theory

What is JavaScript?

• A programming language popular for web development
• Used to give instructions to computers and machines
• Can be run in the browser

How to run JavaScript code?

1. In the browser console
2. Using a code editor (VS Code)

VS Code

• Free, popular, and supports various languages
• How to download and install
• How to create an HTML file and link it with a JavaScript file

First JavaScript Program

• Using console.log to print a message on the console

console.log('Apna College');

• In the console, the code disappears upon refreshing the browser, but the code in the file remains permanent

Variables

• Containers for data
• Can store various types of data (number, string, boolean)

How to declare variables

• Using let, const, and var keywords
• let and const are preferable

Primitive Data Types

• Number: let age = 24;
• String: let name = 'Tony Stark';
• Boolean: let isFollow = true;
• Undefined: let x; // x is undefined
• Null: let x = null;
• BigInt: let x = BigInt(123);
• Symbol: let y = Symbol('hello');

Non-Primitive Data Types

• Objects: Collection of key-value pairs
• Arrays and functions are also objects
• Object example:

const student = {
 fulName: 'Rahul Kumar',
 age: 20,
 cgpa: 8.2,
 isPass: true
};

• Access: Dot notation and bracket notation

Solving Practice Questions

Practice Question 1

• Store data of amazonflex.in

const product = {
 title: 'Parker Jotter Standard CT Ball Pen',
 rating: 4,
 offer: 5,
 price: 270
};
console.log(product);

Practice Question 2

• Store instagram follower data

const profile = {
 userName: 'shraddha_kapoor',
 isFollow: false,
 followers: 2000,
 following: 180
};
console.log(profile);

Notes

• JavaScript is a dynamically typed language
• Styling cases: Camel case, Pascal case, Snake case, Kebab case
• Working on properties and methods of objects

Conclusion

• Covered basics such as variables, data types, and practice questions
• Will go into more detail in future lectures

Keep Learning and Keep Coding