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 ] */