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【Gatsby.js】How to Fix MDXProvider Error 'Warning: The tag <item> is unrecognized in this browser. If you meant to render a React component, start its name with an uppercase letter.'

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Table Of Contents

  1. Error Details
  2. Solution
  3. Conclusion

This article explains how to fix the MDXProvider error 'Warning: The tag <item> is unrecognized in this browser. If you meant to render a React component, start its name with an uppercase letter.' in Gatsby.js.

PR

Error Details

Warning: The tag <item> is unrecognized in this browser. If you meant to render a React component, start its name with an uppercase letter.

Solution

As the error message suggests, component names must be written in uppercase.

Correct Example

import { MDXProvider } from "@mdx-js/react"
import ItemComponent from "../components/item"

const components = {
  Item: ItemComponent,
}

const BlogPostTemplate = ({ data, location, children }) => {
  return <MDXProvider components={components}>{children}</MDXProvider>
}

export default BlogPostTemplate

Incorrect Example

const components = {
  item: ItemComponent,
}

Conclusion

While migrating from .md to .mdx, I encountered this error when trying to use the following approach:

import RehypeReact from "rehype-react"

const renderAst = new RehypeReact({
  createElement: React.createElement,
  components: {
    item: ItemComponent,
  },
}).Compiler

This issue arose when attempting to make it work in MDX as well.

I hope this helps someone facing the same problem.

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