JavaScript const Explained for Beginners – Easy Guide with Examples

Learn what const means in JavaScript with this simple guide for beginners. Understand how to use const with numbers, arrays, and objects, and why it's useful for writing safer code.

🧠 What is const in JavaScript?

const is a way to create a variable in JavaScript, but one that cannot be changed later.
It stands for “constant” — something that stays the same.

📌 Basic Rule

Once you give a value to a const variable, you cannot change that value.

🧾 Syntax

const name = "John";

✅ Easy Examples

1. Constant value:

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

// You can't change it later:
// pi = 3.14159; // ❌ This will give an error

2. With an array (list of items):

const colors = ["red", "blue"];
colors.push("green"); // ✅ You can add items
console.log(colors); // ["red", "blue", "green"]

// colors = ["yellow"]; // ❌ Not allowed: you can't assign a new array

3. With an object:

const user = { name: "Alice", age: 25 };
user.age = 26; // ✅ You can change properties
console.log(user); // { name: "Alice", age: 26 }

// user = { name: "Bob" }; // ❌ Not allowed

💡 When Should Beginners Use const?

• When the value shouldn’t change (like a name, total, or settings).
• It helps avoid mistakes and makes your code easier to read.