functional-iterator

Python-like iterator for JavaScript. The library implements lazy iteration over arrays and provides functions .map, .filter, and .reduce on the iterator.

Chaining doesn't copy arrays on each step and doesn't waste memory. Real calculations perform only on actual data consuming - on reduce, join, and toArray calls.

funcIterator([1, 2, 3, 4, 5])
  .map((el) => el * 2)
  .filter((el) => el > 3)
  .reduce((previousValue, currentValue) => previousValue + currentValue, 0);