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What is pop in JavaScript

Breaking Down the pop() Method

If you're learning JavaScript, you'll find yourself dealing with arrays quite often. Among the many methods that JavaScript provides for manipulating arrays, pop() is one of the most commonly used. But what exactly is pop(), how does it work and when should we use it? Let's dive right in.

Meet The pop() Method

The pop() method is like a magic trick for arrays. Imagine an array is a line of people waiting for a bus. The pop() method is the bus that picks up the last person in line and whisks them away. In JavaScript terms, pop() removes the last element from an array and returns that element. Here's how it looks in action:

let arr = [1, 2, 3, 4, 5];
let lastElement = arr.pop();
console.log(arr); // Output: [1, 2, 3, 4]
console.log(lastElement); // Output: 5

Understanding How pop() Works

As you see in the example above, invoking pop() on an array causes two things to happen. First, it removes the last element from the array. Second, it returns the value of the removed element. What's important to note is that the original array is changed. This is what we call a destructive method, meaning it alters the original data.

The Return Value of pop()

The pop() method doesn't just remove the last element, it also returns it. This is like the bus driver handing you a note with the name of the last passenger they picked up. This can be useful if you want to use the value of the removed element later in your code.

let arr = ['apple', 'banana', 'cherry'];
let lastFruit = arr.pop();
console.log(lastFruit); // Output: 'cherry'

In this example, we've popped 'cherry' off the end of our fruits array and stored it in the lastFruit variable for later use.

When To Use pop()

The pop() method is perfect for situations where you want to work with elements in a Last-In-First-Out (LIFO) manner. This might sound like a mouthful, but it's a common concept in programming. It's like a stack of plates: the last plate you put on the stack is the first one you'll remove.

In JavaScript, you might use pop() when implementing features such as undo functionality (where the most recent action is the first to be undone), or in algorithms like depth-first search, where the most recently discovered node is the first to be explored.

pop() With Empty Arrays

What happens if we use pop() on an empty array? Let's find out:

let arr = [];
let lastElement = arr.pop();
console.log(lastElement); // Output: undefined

When pop() is called on an empty array, it returns undefined. This is because there's no 'last element' to remove and return.


In the journey of JavaScript's array methods, the pop() method is an important companion to have. It's like a trusty pocketknife; not the most glamorous tool, but practical in many situations. Whether you're building a stack, creating an undo feature, or just need to quickly remove the last element from an array, pop() is ready to help.

As with any tool, the key to using it effectively is understanding how it works. We've seen that pop() is a destructive method that operates on a Last-In-First-Out basis, and it's important to keep these characteristics in mind when using it in your code.

So the next time you find yourself dealing with arrays, remember the pop() method. Like a reliable bus service, it's always there to pick up the last passenger, and it won't leave you stranded even if the queue is empty.