viewof progress = {
const progressMeter = html`<progress value=0 max=1000></progress>`
yield progressMeter;
let sum = 0;
for (let i = 0, n = 1000; i < n; ++i) {
sum += 1;
progressMeter.value = sum;
await new Promise(requestAnimationFrame);
}
progressMeter.value = sum;
return progressMeter;
}