function sequence(newStart, newStep) {

    var currentCount = newStart ? newStart : 0;

    return function() {

        currentCount = newStep ? currentCount + newStep : ++currentCount;

        return currentCount;

    }

}

​

​

function take(func, numOf) {

    var arr = [];

    for ( var i = 0; i < numOf; i++) {

        arr[i] = func();

    }

    return arr;

}

​

​

var gen2 = sequence(0, 2);

console.log(take(gen2, 5)); // [0, 2, 4, 6, 8 ]