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Fetch users from GitHub

Create an async function getUsers(names), that gets an array of GitHub logins, fetche the users from GitHub and returns an array of GitHub users.

The GitHub url with user informaiton for the given USERNAME is: https://api.github.com/users/USERNAME.

There’s a test example in the sandbox.

Important details:

  1. There should be one fetch request per user. And requests shouldn’t wait for each other. So that the data arrives as soon as possible.
  2. If any request fails, or if there’s no such user, the function should return null in the resulting array.

Open a sandbox with tests.

To fetch a user we need:

  1. fetch('https://api.github.com/users/USERNAME').
  2. If the response has status 200, call .json() to read the JS object.

If a fetch fails, or the response has non-200 status, we just return null in the resulting arrray.

So here’s the code:

async function getUsers(names) {
  let jobs = [];

  for(let name of names) {
    let job = fetch(`https://api.github.com/users/${name}`).then(
      successResponse => {
        if (successResponse.status != 200) {
          return null;
        } else {
          return successResponse.json();
        }
      },
      failResponse => {
        return null;
      }
    );
    jobs.push(job);
  }

  let results = await Promise.all(jobs);

  return results;
}

Please note: .then call is attached directly to fetch, so that when we have the response, it doesn’t wait for other fetches, but starts to read .json() immediately.

If we used await Promise.all(names.map(name => fetch(...))), and call .json() on the results, then it would wait for all fetches to respond. By adding .json() directly to each fetch, we ensure that individual fetches start reading data as JSON without waiting for each other.

That’s an example of how low-level Promise API can still be useful even if we mainly use async/await.

Open the solution with tests in a sandbox.