Function scope in Javascript - Mini Project: Build & Apply

Function scope

📖 Scenario: Imagine you are organizing a small event and you want to keep track of the number of guests inside the event hall. You will use functions to manage this count, but you want to understand how variables inside and outside functions behave.

🎯 Goal: You will create a variable to count guests, write a function that changes this count inside its own scope, and then see how the count changes outside the function.

📋 What You'll Learn

Create a variable called guestCount and set it to 10

Create a function called addGuests that declares a local variable guestCount and sets it to 20

Inside the function addGuests, print the local guestCount

Outside the function, print the original guestCount variable

💡 Why This Matters

🌍 Real World

Understanding function scope helps avoid bugs when managing data in different parts of a program, like counting guests or tracking inventory.

💼 Career

Many programming jobs require clear understanding of variable scope to write clean, bug-free code.

1

Create the initial guest count variable

Create a variable called guestCount and set it to 10.

Javascript

// Create a variable called guestCount and set it to 10
// Your code here

Need a hint?

Use let to create the variable guestCount and assign it the value 10.

2

Create a function with a local guestCount variable

Create a function called addGuests that declares a local variable guestCount and sets it to 20.

Javascript

let guestCount = 10;
// Create a function called addGuests with a local guestCount variable set to 20
// Your code here

Need a hint?

Inside the function addGuests, declare a new variable guestCount using let and assign it 20.

3

Print the local guestCount inside the function

Inside the function addGuests, add a line to print the local guestCount using console.log.

Javascript

let guestCount = 10;

function addGuests() {
    let guestCount = 20;
    // Print the local guestCount
    // Your code here
}

Need a hint?

Use console.log(guestCount); inside the function to print the local variable.

4

Call the function and print the original guestCount

Call the function addGuests() and then print the original guestCount variable using console.log.

Javascript

let guestCount = 10;

function addGuests() {
    let guestCount = 20;
    console.log(guestCount);
}

// Call addGuests and print the original guestCount
// Your code here

Need a hint?

Call addGuests() first, then print guestCount with console.log(guestCount);.