updates

5-network/01-fetch/01-fetch-users/solution.md

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+
+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:
+
+```js demo
+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`.