myStack_array.js

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

    // Peek the top element.
    peek() {
        this.list.length ? console.log(this.list[this.list.length - 1]) : console.log('The stack is empty.');
        return this.list.length;
    }

    // Push the element.
    push(value) {
        this.list.push(value);

        console.log(this.list);
        return this.list.length;
    }

    // Pop the last element.
    pop() {
        this.list.length ? console.log(this.list.pop()): console.log('The stack is empty.');
        return this.length;
    }
}

const myStack = new Stack();

myStack.push('Udemy');                  // [ 'Udemy' ]
myStack.push('Google');                 // [ 'Udemy', 'Google' ]
myStack.push('Discord');                // [ 'Udemy', 'Google', 'Discord' ]

myStack.peek();                         // Discord

myStack.pop();                          // Discord
myStack.pop();                          // Google
myStack.pop();                          // Udemy
myStack.pop();                          // The stack is empty.