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How can I add a custom MDX component?

Here's an example on how to create a donut chart from Chart.js (assuming you already have the dependencies installed) and use it in MDX posts. First, create a new DonutChart.tsx component in components:

'use client'

import { Doughnut } from 'react-chartjs-2'
import { Chart as ChartJS, ArcElement, Tooltip, Legend } from 'chart.js'

ChartJS.register(ArcElement, Tooltip, Legend)

const DonutChart = ({ data }) => {
  return <Doughnut data={data} />
}

export default Doughnut

Since the underlying Doughnut component uses React hooks, we add the 'use client' directive to specify that it is a client side component. Also, there is an existing issue which prevents named components from being used, so we need to export the component as the default export.

Next, add the component to MDXComponents.tsx:

...
+ import DonutChart from './DonutChart'

export const components: MDXComponents = {
  Image,
  TOCInline,
  a: CustomLink,
  pre: Pre,
+  DonutChart,
  BlogNewsletterForm,
}

You can now use the component in .mdx files:

## Example Donut Chart

export const data = {
  labels: ['Red', 'Blue', 'Yellow'],
  datasets: [
    {
      label: '# of Votes',
      data: [12, 19, 3],
      backgroundColor: [
        'rgba(255, 99, 132, 0.2)',
        'rgba(54, 162, 235, 0.2)',
        'rgba(255, 206, 86, 0.2)',
      ],
      borderColor: ['rgba(255, 99, 132, 1)', 'rgba(54, 162, 235, 1)', 'rgba(255, 206, 86, 1)'],
      borderWidth: 1,
    },
  ],
}

<DonutChart data={data} />