gistfile1.txt

The problem: Use forEach to write a function that behaves like filter.

The correct answer:

function filter(arr, callback) {
  const newArr = [];
  
  arr.forEach((el) => {
    if (callback([el])) {
      newArr.push(el)
    } 
  })
  return newArr;
}

The tests that had to pass:


>
filter([1, 2, 3], num => num >= 0)
Expected: [1, 2, 3] OK!

>
filter([1, 2, 3], num => num > 1)
Expected: [2, 3] OK!

>
filter([1, 2, 3], num => num > 5)
Expected: [] OK!

>
filter([null, undefined], num => true)
Expected: [null, undefined] OK!

>
filter([], num => true)
Expected: [] OK!

>
// You must use `forEach`.
filter.toString().includes('forEach')
Expected: true OK!

>
// You must use a stack function.
const code = filter.toString()
code.includes('pop') || code.includes('push')
Expected: true OK!