I&#x27;m very excited about:<p><pre><code>    React.Children.map now returns plain arrays too
</code></pre>
Before this change, we would have to do the following when checking the types of children components (in propType validation):<p><pre><code>    const childrenTypes = [];
    React.Children.forEach(props.children, child =&gt; {
      childrenTypes.push(child.type);
    });
    for (const type of childrenTypes) {
      if (type !== MyComponent) {
        return new Error(`Child &#x27;${type}&#x27; is not an instance MyComponent. Check render method of &#x27;ParentComponent&#x27;.`);
      }
    }
</code></pre>
It sort of made sense that map() on an opaque data structure would return the same type of data structure but in practice this was rarely useful.<p>Thanks, React team!