Streams of Asynchronous Data

Sometimes data doesn't arrive all at once — it comes in chunks (like lines from a huge file, or pages from a paginated API). Async generators solve this elegantly.

async function* fetchAllCommits(repo) {
  let url = `https://api.github.com/repos/${repo}/commits`;
  
  while (url) {
    const response = await fetch(url); // Wait for each page
    const commits = await response.json();
    
    yield* commits; // Yield each commit one by one
    
    // Get the URL for the next page from the Link header
    const linkHeader = response.headers.get('Link');
    url = parsNextPageUrl(linkHeader); // null if no more pages
  }
}

// Consume: iterate through all commits, page by page
for await (const commit of fetchAllCommits('microsoft/vscode')) {
  console.log(commit.sha, commit.commit.message);
}

Why This Pattern Is Powerful

The consumer code is clean and sequential. It doesn't need to know about pagination at all — it just iterates until there's nothing left. The generator handles all the network logic internally.