Day 1 - Session 2: JavaScript Basics (Datatypes,Variables, Functions & More)

Hello Devs!

In today’s session, we’re diving deeper into JavaScript fundamentals. If you’re just getting started, this will help set a solid base. Let’s break it down simply.

1.Datatypes:

JavaScript has different types of data you can work with. The most common are:

• String→ text → "Hello World"
• Number → numbers → 42, 3.14
• Boolean → true/false → true, false
• Undefined→ no value assigned
• Null → intentionally empty
• Object → key-value pairs → {name: "Alex"}
• Array→ list of items → [1, 2, 3]

⮞ Example:

let name = "Alex"; // string
let age = 25; // number
let isStudent = true; // boolean

2.Variables:

We store data in variables. In modern JS, we mostly use:

•let → value can change
•const→ value cannot change (constant)

⮞ Example:

let city = "New York";
city = "London"; // this works

const country = "USA";
// country = "Canada"; //  error

3.Functions

A function is a reusable block of code that performs a task.

⮞ Example:

function greet() {
    console.log("Hello!");
}

We call or invoke a function like this:

greet(); // Output: Hello!

4.Return & Arguments

Functions can take arguments (inputs) and return outputs.

⮞ Example:

function add(a, b) {
    return a + b;
}

let sum = add(5, 3); // sum = 8
console.log(sum); // Output: 8

5.String Concatenation

We combine (concatenate) strings using +.

⮞ Example:

let firstName = "Alex";
let lastName = "Smith";
let fullName = firstName + " " + lastName;
console.log(fullName); // Output: Alex Smith

6.Quick Recap

✔ Datatypes help define the kind of data.
✔ Variablesstore data.
✔ Functions let us organize reusable logic.
✔ Arguments & returnallow input and output.
✔ Concatenation connects strings.

That’s a wrap for Session 2!

Thanks for reading — happy coding!!!