Lazy comprehention

lazy_comprehention.js

function take(n, str) {
  function _take(n, str, accum) {
    if (n === 0) {
      return accum;
    }
 
    const { value, next } = str();
 
    return _take(n - 1, next, accum.concat(value));
  }
 
  return _take(n, str, []);
}

function stream(fn, initial) {
  function _stream(value) {
    return {
      value,
      next() {
        return _stream(fn(value));
      }
    };
  }
 
  return () => _stream(initial);
}

function smap(fn, originalStr) {
  function _stream(str) {
    const { value, next } = str();
 
    return {
      value: fn(value),
      next() {
        return _stream(next);
      }
    };
  }
 
  return () => _stream(originalStr);
}
 
function sfilter(fn, originalStr) {
  function _stream(str) {
    const { value, next } = str();
 
    if (fn(value)) {
      return {
        value,
        next() {
          return _stream(next);
        }
      };
    }
 
    return _stream(next);
  }
 
  return () => _stream(originalStr);
}

function lazyComprehention(map_fn,str,filter_fn){
  return smap(map_fn,sfilter(filter_fn,str));
}

const nats = stream(n => n + 1, 1);
squared_odd_numbers = lazyComprehention(n => n * n, nats, n => n % 2 !== 0)
console.log(take(10,squared_odd_numbers)); // [1, 9, 25, 49, 81, 121, 169, 225, 289, 361]