let arr = [ 7, 8, 5, 8, 9 ];
// a : filterBy is not a function
//let arr1 = arr.map((num) => (num*2)).filterBy((val) => ( val > 15 ));
// b : return error
//let arr1 = arr.mapBy((num) => (return num*2)).filterBy ((val) => return val > 15 ));
// c
let arr1 = arr.map((num) => num*2).filter((val) => val > 15);
// d : return error
//let arr1 = arr.filter((val) => (return val > 15 )).map ((num) => (return num *2));
console.log(arr1);
https://onecompiler.com/javascript/3ynnbj89f