What is this type?!

If you’re new to TypeScript and you’re using a library like react-emotion, you might be wondering how to type your styled components. Here’s what I do.

Let’s say you have the following styled component:

What is the type for AStyledComponent?

I don’t know, but VSCode is here to save the day:

The above image shows me hovering over AStyledComponent and VSCode showing me what type it is. We can then use this type:

But…what are all these type definitions? And, where do they come from?

Well, after some digging around in react-emotion, create-emotion-styled and react itself — I found these awesome imports:

Note: When I say “digging” I meant going into node_modules/react-emotion, node_modules/create-emotion-styled and looking in their type definitions file (index.d.ts ).

As for the parameters for StyledOtherComponent<A, B, C> :

• A, denoted as any in the images above, is for the properties used within the style definition.
• B, denoted as DetailedHTMLProps<HTMLAttributes<HTMLDivElement>, HTMLDivElement> is for the component you are wrapping.
• C, denoted as any, is for a theme.

Alright! That’s all I have for you folks today. Let me know if you have any questions or feedback — I’d love to hear it.

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