Question about this React syntax

[fconijn]

On https://blog.hubspot.com/website/react-js, the principle of React is explained quite well. But at about halfway the page, just under “Step 3: Crafting the React Component” there is a syntax that I don’t understand.

It’s about the line ReactDOM.render(, container);

That does not call the constant ActualWidget, so how does the browser know that it should fill the container with Hello World?

[Zensei]

I would said is a mistake that the author haven’t notice while writing the blog.

But of course it would to be tested in code to make sure that is the case.

[fconijn]

That’s what it indeed would look like. Unfortunately, the author doesn’t give his contact details.

[Zensei]

Here is the test. How you can see it error out

Now no error. Hello world is printed