test.js

function* g() {
  let i = 0;
  while (i++ < 4) {
    console.log(i);
    yield i;
  }
  console.log('done');
}

function mapper(x) {
  console.log('map', x);
  return x * 2;
}

Array.from(g(), mapper);
/*
1
map 1
2
map 2
3
map 3
4
map 4
done
[ 2, 4, 6, 8 ]
*/

Float32Array.from(g(), mapper);
/*
1
2
3
4
done
map 1
map 2
map 3
map 4
Float32Array [ 2, 4, 6, 8 ]
*/