title: React, problem with mapping by the child component
body: <p>I've got a problem with rendering components,
  I have a component named 'Task' that is mapped by 'app' like:</p>
  <pre><code>{tasks.map((e, index) =&gt;
      &lt;Task key={e.id} title={e.title} description={e.description} id={e.id} status={e.status} remove={onRemoveTask}/&gt;
      )}
  </code></pre>
  <p>with state of operations like (Task component):</p>
  <pre><code>const [operations, setOperations] = useState([])
      useEffect(() =&gt; {
          async function apiCall() {
              try {
                  const data = await getOperations(id);
                  setOperations(data)
              } catch(err) {
                  console.log(err)
              }
          }
          apiCall();
      }, [])
  </code></pre>
  <p>After <em>console.log(operations)</em> there is a list of operations for each task.
  The problem is, why I cannot map this array like:</p>
  <pre><code>{operations.map((e, index) =&gt; {
      &lt;Operation key={e.id} operation={e}/&gt;
  })}
  </code></pre>
  <p>It renders nothing.</p>