array-factory

const myArray = [1, 2, 3]
// Only even numbers
for (const item of myArray.factoryFilter(el => !(el % 2))) {
  console.log(item)
}

{@link https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Array/flat#use_generator_function}

const myArray = [1, 2, [3, 4]]
for (const item of myArray.factoryFlat()) {
  console.log(item)
}
// 1, 2, 3, 4

const myArray = [1, 2, 3]
for (const item of myArray.factoryFlatMap(el => [el, el * 2])) {
  console.log(item)
}
// 1, 2, 2, 4, 3, 6

const myArray = [1, 2, 3]
for (const item of myArray.factoryMap(el => el * 2)) {
  console.log(item)
}