Generates the Fibonacci sequence using Iterable function

fibonacci.ts

function* fib(n: number) {
    if(n <= 1) {
        yield 0;
    }
    else {
        let twoBefore = 0, oneBefore = 1;
        yield twoBefore;
        yield oneBefore;
        for(let i = 2; i < n; ++i) {
            const current = twoBefore + oneBefore;
            twoBefore = oneBefore;
            oneBefore = current;
            yield current;
        }
    }
}

for(const i of fib(6)) console.log(i); // 0 1 1 2 3 5
console.log([...fib(6)]); // [0, 1, 1, 2, 3, 5]