Using Generators to lazily build a collection of items in ES6 (babeljs)

LazyCollection.js

// Infinitely generate all odd numbers or whatever the MAX Number is
function* oddNumbers() {
  let i = 1
  
  // Infinite loop. But thanks to the yield keyword, we exit this
  // loop and return a value. On the next call back in, we resume
  // where we left off.
  while(1) {
    yield i;
    
    // Imagine if this were an expensive computation
    i += 2;
  }
}

// Materialize n items from the iterable collection and place them
// in a new array
function take(n, iterable) {
  let count = 0;
  let taken = [];
  
  for (let value of iterable) {
    if (count >= n) {
      break;
    }
    
    taken[count] = value;
    count++;
  }
  
  return taken;
}

// Materialize 10 odd numbers in an array
console.log(take(10, oddNumbers()));

// Output should be:
// [1,3,5,7,9,11,13,15,17,19]