01-Stack.js

// import Stack from './../../src/js/data-structures/stack.js'; // ES2015 modules
// import StackArray from './../../src/js/data-structures/stack-array.js'; // ES2015 modules
// const Stack = require('../../dist/js/data-structures/stack'); // for node
// const Stack = stack; // older browsers - remove from html script import: type="module"
const { Stack } = PacktDataStructuresAlgorithms;

const stack = new Stack(); // new StackArray();

// using WeakMap to store Stack items we ensure true privacy
// console.log(Object.getOwnPropertyNames(stack));
// console.log(Object.keys(stack));
// console.log(stack.items);

console.log('stack.isEmpty() => ', stack.isEmpty()); // outputs true

stack.push(5);
stack.push(8);

console.log('stack after push 5 and 8 => ', stack.toString());

console.log('stack.peek() => ', stack.peek()); // outputs 8

stack.push(11);

console.log('stack.size() after push 11 => ', stack.size()); // outputs 3
console.log('stack.isEmpty() => ', stack.isEmpty()); // outputs false

stack.push(15);

stack.pop();
stack.pop();

console.log('stack.size() after push 15 and pop twice => ', stack.size()); // outputs 2