Javascript Programming Tutorials, Guides & Best Practices

A stack is a LIFO (Last In, First Out) data structure. The most recent element added is the first one to be removed.

class Stack {
    constructor() {
        this.items = [];
    }

    push(element) {
        this.items.push(element);
    }

    pop() {
        if (this.isEmpty()) return "Underflow";
        return this.items.pop();
    }

    peek() {
        return this.items[this.items.length - 1];
    }

    isEmpty() {
        return this.items.length === 0;
    }

    printStack() {
        let stackString = "";
        for (let i = 0; i < this.items.length; i++) {
            stackString += this.items[i] + " ";
        }
        return stackString;
    }
}

let stack = new Stack();
stack.push(10);
stack.push(20);
stack.push(30);
console.log(stack.printStack()); // Output: 10 20 30
stack.pop();
console.log(stack.printStack()); // Output: 10 20