Handling asynchrony

The basic tools are callbacks, Promises and async/await. Events and streams, in turn, suit a series of results, e.g. data arriving over a connection.

async function load() {
  try {
    const response = await fetch('https://example.com/api/items');
    if (!response.ok) throw new Error(`HTTP ${response.status}`);
    return await response.json();
  } catch (error) {
    console.error('Failed to fetch data', error);
    throw error;
  }
}

Pitfall: fetch doesn't reject its Promise just because the server returned HTTP 404 or 500. You have to check the status. For real requests I also plan a timeout and cancellation.