/**

* Implementation of stack with an array

*/

class Stack {

constructor() {

this.stack = [];

}

// Insert an element on top of the stack

push(element) {

this.stack.push(element);

}

//Removes the element at the top of the stack and returns that same element

pop() {

if (this.isEmpty())

return 'Stack is empty!';

return this.stack.pop();

}

// Returns the element that is on top of the stack

peek() {

if (this.isEmpty())

return 'Stack is empty';

return this.stack[this.stack.length - 1];

}

// helper method

isEmpty() {

return !this.stack.length;

}

}