dpalita

const observableOfOddSquares =
// observable source
Observable.of(
   // stream d'entier
   1, 2, 3, 4, 5, 6
)
// observer du stream d'entier, observable d'impairs
.filter(num => num % 2)
// observer du stream d'impairs, observable de carrés d'impairs
.map(odd => odd * odd)

dpalita

const fetchNews = (subject: string): Promise<News[]> => {
    return fetch('http://newsApi?subject=' + subject)
              // promise
              .then(res => res.text() /* re promise ^^ */)
}
const trumpNews = fetchNews('Trump')
const kimNews = fetchNews('Kim Jong-Un')
trumpNews.then(news => readNewsAndLaugh(news))
kimNews.then(news => readNewsAndLaugh(news))
Promise.all(trumpNews, kimNews)

dpalita

const square = (operand: number): number =>  operand * operand
const four = square(2)