[ES6] Generators

function *topicList(){
  yield "ES2015";
  yield "Semi-colons: good or bad?";
  yield "TypeScript";
}

for( let topic of topicList() ){
  console.log( topic );
}

let user = {
  name: "sam", totalReplies: 17, isBlocked: false
};

user[Symbol.iterator] = function  *(){for(let p of properties){
    yield this[p];
  }
};

for(let p of user){
  console.log( p );
}