Article Categories

Selected Reading

How to create a unique ID for each object in JavaScript?

Javascript Web Development Object Oriented Programming

In JavaScript, creating unique IDs for objects is essential for tracking and identifying instances. The most reliable method is using Symbol(), which generates guaranteed unique identifiers.

Using Symbol() for Unique IDs

The Symbol() function creates a unique symbol every time it's called, even with the same description. This makes it perfect for generating unique object identifiers.

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Unique Object IDs</title>
    <style>
        body {
            font-family: "Segoe UI", Tahoma, Geneva, Verdana, sans-serif;
        }
        .result {
            font-size: 18px;
            font-weight: 500;
            color: rebeccapurple;
            margin: 20px 0;
        }
        button {
            padding: 10px 20px;
            font-size: 16px;
            background-color: #007bff;
            color: white;
            border: none;
            border-radius: 5px;
            cursor: pointer;
        }
    </style>
</head>
<body>
    <h1>Create Unique IDs for Objects</h1>
    <div class="result"></div>
    <button class="btn">Check ID Uniqueness</button>
    <h3>Click the button to verify that each object has a unique ID</h3>

    <script>
        let resEle = document.querySelector(".result");
        let btnEle = document.querySelector(".btn");
        
        // Create objects with unique Symbol IDs
        let obj1 = {
            id: Symbol("UID"),
            name: "Object 1",
            value: 100
        };
        
        let obj2 = {
            id: Symbol("UID"),
            name: "Object 2", 
            value: 200
        };
        
        btnEle.addEventListener("click", () => {
            if (obj1.id === obj2.id) {
                resEle.innerHTML = "IDs are NOT unique!";
            } else {
                resEle.innerHTML = `
                    <strong>IDs are unique!</strong><br>
                    Object 1 ID: ${obj1.id.toString()}<br>
                    Object 2 ID: ${obj2.id.toString()}
                `;
            }
        });
    </script>
</body>
</html>

Alternative Methods

Here are other approaches for generating unique IDs:

// Method 1: Using Date.now() + Math.random()
function generateUniqueId() {
    return Date.now().toString(36) + Math.random().toString(36).substr(2);
}

let obj1 = { id: generateUniqueId(), data: "test1" };
let obj2 = { id: generateUniqueId(), data: "test2" };

console.log("Object 1 ID:", obj1.id);
console.log("Object 2 ID:", obj2.id);
console.log("Are IDs unique?", obj1.id !== obj2.id);

// Method 2: Using crypto.randomUUID() (Node.js 14.17+)
if (typeof crypto !== 'undefined' && crypto.randomUUID) {
    let obj3 = { id: crypto.randomUUID(), data: "test3" };
    console.log("UUID ID:", obj3.id);
}

Object 1 ID: l4d2k7j1g7h
Object 2 ID: l4d2k7j3m9n
Are IDs unique? true
UUID ID: 550e8400-e29b-41d4-a716-446655440000

Comparison of Methods

Method	Uniqueness	Readability	Use Case
`Symbol()`	Guaranteed	Low	Object properties, internal tracking
`Date.now() + Math.random()`	Very High	Medium	General purpose IDs
`crypto.randomUUID()`	Guaranteed	High	Standard UUIDs for APIs

Key Points

Symbol() creates truly unique identifiers that cannot be duplicated
Even with the same description, each Symbol is unique
Symbols are not enumerable in for...in loops
Use crypto.randomUUID() for standard UUID format

Output

Conclusion

Use Symbol() for guaranteed unique object IDs. For human-readable IDs, combine Date.now() with Math.random() or use crypto.randomUUID() for standard UUID format.

AmitDiwan

Updated on: 2026-03-15T23:18:59+05:30

1K+ Views

Kickstart Your Career

Get certified by completing the course

Get Started

Previous Next