Tony Yip says to YSITD
/* Get stock data somehow */ const source = getAsyncStockData(); const subscription = source .filter(quote => quote.price > 30) .map(quote => quote.price) .subscribe( price => console.log(`Prices higher than $30: ${price}`), err => console.log(`Something went wrong: ${err.message}`) ); /* When we're done */ subscription.dispose();