<file_sep>"use strict";

var test = "Hello";<file_sep>'use strict';

var theString = "Hello, I love Javascript";

console.log(theString.includes('love'));

function greet() {
  var greeting = arguments.length > 0 && arguments[0] !== undefined ? arguments[0] : 'Hello World';

  console.log(greeting);
}

greet();<file_sep># es6
1. Set is a container that have unique values in it.
2. It has function like, add, delete.
3. Loop on set can be done by forEach method.


Map
1. Map are key value pairs.
2. You can add & delete key values in map through set and delete method.

WeakSet (unique objects collection - WeakSet objects are collections of objects. An object in the WeakSet may only occur once; it is unique in the WeakSet's collection.)
1. add and delete methods are used.


WeakMap  (objects map, where key and value are both objects)
1. set and delete methods are used.
<file_sep>'use strict';

var myArray = [11, 33, 22, 44, 11];
var mySet = new Set(myArray);

console.log(mySet);

mySet.add('tom');
mySet.add(12);
mySet.delete(22);

mySet.forEach(function (val) {
  console.log(val);
});<file_sep>class User {
  constructor(username, email, password){
    this.username = username;
    this.email = email;
    this.password = <PASSWORD>;
  }

  register(){
    console.log(this.username + ' is now registered.');
  }
}

class Member extends User {
  constructor(username, email, password, memberPackage){
    super(username, email, password);
    this.memberPackage = memberPackage;
  }

  getPackage(){
    console.log(this.username + ' is now a Member');
  }
}

let bob = new User('bob', '<EMAIL>', '12345');
bob.register();

let alice = new Member('Alice', '<EMAIL>', '2212', 'Sys');
alice.getPackage();
