The goal of this task is to create an implementation of stack. We would like it to be initialized as this:

const stack = new Stack()

It should also allow to create a stack with initial values like this:

const stack = new Stack('abc', 123, true)

The stack should implement the following methods:

• push – pushes a new element on top of a stack
• pop – removes top element from a stack; if the stack is empty it should return null
• peek – takes top element from a stack but doesn't remove it
• swap – swaps position of the top two elements
• isEmpty – returns boolean based on whether a stack is empty or not

The stack should also implement size property which will return an actual stack size.

Project contains a set of simple tests. In a working solution all tests should be passing.

To run it first install dependencies:

$ yarn install

To run tests:

$ yarn test

Good luck! Team Albacross