adding validation for peek and returning last element from array with…

[gautam-paladiya]

…out calculating length

[sudheerj]

@gautam-paladiya Thanks for your PR. Let's use a standway to access the array item.

peek() {
// Check if the stack is empty
if (this.isEmpty()) {
throw new Error("Stack Underflow: Cannot peek from an empty stack");
}
// Return the top most element from the stack without removing it
return this.array[this.array.length - 1];
}

[gautam-paladiya]

Accepted please go ahead