export function fibonacci(value) {
  let previous0 = 0, previous1 = 1;
  let nextValue = 0;
  if (value === 0) {
    nextValue =  0;
  } else if (value === 1) {
    nextValue =  1;
  }
  for (let i = 2; i <= value; i++) {
    nextValue = previous0 + previous1;
    previous0 = previous1;
    previous1 = nextValue;
  }
  return nextValue;
}