/*

  Functional Programming in JavaScript

  Author: Luis Atencio

  Exercise 4

  Trying map, reduce, and filter

*/

console.log('Map, Reduce, Filter');

​

var numbers = [1, 2, 3, 4, 5, 6, 7, 8 , 9];

​

/*

 Task is to square each number,

 remove any odd ones, and total the rest

*/

var result = _(numbers)

              .map((x) => x * x)

              .filter((x) => x % 2 !== 0)

              .reduce((total, x) => total + x);

​

console.log('Result is: ' + result);

​

​

/* 

 EXERCISE: Change map to subtract 5 from each number

           Change filter to eliminate any negatives

           Resut should be 10

*/

result = _(numbers)

              .map((x) =>    /* FINISH */)

              .filter((x) => /* FINISH */)

              .reduce((total, x) => total + x);

​

console.log('Your Result is: ' + result);

console.log(result === 10 ? 'good job!' : 'Try again!');

​