es6/7 fib

es6_fib.js

function* fib(num) {
  var prev = 0;
  var curr = 1;
  while (curr < num) {
  	var tmp = prev;
  	prev = curr;
    curr = tmp + curr;
    yield curr;
  }
}

for (var i of fib(10)){
console.log(i)
}