Constants

Part of the Fundamentals section of Coddy's JavaScript journey — lesson 11 of 77.

In JavaScript, sometimes you need variables that never change. This is where const comes in! It’s used to create constants—values that stay the same after being set.

Use the const keyword, just like let, but once you set its value, you cannot change it later.

const pi = 3.14;
console.log(pi); // Output: 3.14

// Trying to change pi will cause an error:
pi = 3.14159; // Error: Assignment to constant variable.

Use const for values that should never change, like:

Mathematical constants (pi = 3.14)
Fixed settings (maxUsers = 100)

By using const, your code is safer and easier to understand!

Challenge

Beginner

Initialize a constant variable named minSize with the value of 50

Try it yourself

// Type your code below


// Don't change the line below
console.log(`minSize = ${minSize}`)

Test yourself

This lesson includes a short quiz. Start the lesson to answer it and track your progress.

All lessons in Fundamentals

1Introduction

The Language Hello World!Comments Code Structure

4Operators Part 2

Logical Operators Part 1 Logical Operators Part 2 Recap - Simple Logic Logical Operators Part 3 Type Coercion

7Bill Split Calculator

Welcome Message Calculating The Tip And Total

Splitting The Bill

Formatted Output

10FizzBuzz with a Twist

Game Overview The FizzBuzz Function

Looping The Numbers

Adding The Twist

13Grocery List Tracker

Project Overview Add Item

Remove Item

View List

2Variables

Numbers String Boolean Naming Conventions Empty Variables Recap - Initialize VariablesConstants

5Decision Making

If Statement If - Else Recap - Simple Calculator Nested If - Else Switch Statement

8Loops

For Loop While Loop Break Continue Recap - Factorial Do While Loop Nested Loop

11Arrays Part 1

Declaring an Array Accessing Array Elements Modifying Arrays Array Methods Part 1 Array Methods Part 2 Recap - Array Processor

14Final Challenges

Number Pyramid Double The Odds What To Buy