Instead of generators in ES6(Douglas Crockford's pattern). Returns next element of the array each time when generator inner function invokes.

factoryFunction.js

// Simple array
const myArray = [4,5,6];

const factoryFunction = (array) => {
  // The generator's state variable(s)
	let i = 0;

	return function generator() {
		if(i < array.length) {
      // Compute the new value
			let value = array[i];
      // Update the state variable(s)
			i += 1;
			return value;
		}
	}
};

const newInstance = factoryFunction(myArray);

newInstance(); // 4
newInstance(); // 5
newInstance(); // 6
newInstance(); // undefined