GoodChainedCalls.js

// Using ES6 arrow functions

// Returns true if all even numbers doubled from @numbers are above 5
function doubleEvenNumbers(numbers) { 
  return numbers
          .filter(x => x % 2 == 0)  // Odd numbers removed  
          .map(x => x*2)            // Even numbers doubled
          .every(x => x > 5);       // Are they all above 5 ?
}

console.log(doubleEvenNumbers([3,4,5,6]))
// => True, because doubled array is [8,12]