Error: Must use import to load ES Module: D:\node_modules\react-markdown\index.js require() of ES modules is not supported

Question

Currently I'm using "react": "17.0.2" and I have installed "react-markdown": "^7.0.1" via npm i react-markdown I'm using this package to display my rich text that I'm fetching from my Strapi CMS. I have used the following code to display the content:

import ReactMarkdown from "react-markdown";

export default function name({ posts }) {
  return (
    <>
      <div>
        <div>
          {posts.Title}
        </div>
      </div>
      <div>
        <ReactMarkdown source={posts.Content} escapeHtml={false} />
      </div>
    </>
  );
}

export async function getStaticProps() {
  const res = await fetch("http://localhost:1337/blogs");
  const posts = await res.json();

  return {
    props: { posts },
  };
}

But when I run this it gives me the following error:

I'm using node v14.17.0 and have tried adding "type": "module" .

My package.json:

{
  "name": "passportlegacy",
  "version": "0.1.0",
  "private": true,
  "scripts": {
    "dev": "next dev",
    "build": "next build",
    "start": "next start",
    "lint": "next lint"
  },
  "dependencies": {
    "axios": "^0.21.1",
    "babel-plugin-inline-react-svg": "^2.0.1",
    "next": "11.0.1",
    "next-images": "^1.8.1",
    "react": "17.0.2",
    "react-dom": "17.0.2",
    "react-map-gl": "^6.1.16",
    "react-markdown": "^7.0.1",
  },
  "devDependencies": {
    "@svgr/webpack": "^5.5.0",
    "@types/react": "17.0.16",
    "eslint": "7.32.0",
    "eslint-config-next": "11.0.1",
    "typescript": "4.3.5"
  }
}

Answer 1

I solved this by just pinning react-markdown to version 6.

With version 7 of react-markdown they moved to ESM only. There's a explanation of what that means here , but it seems Jest (version 27) still only has experimental support for pure ESM modules as of October 2021. I couldn't get it to work in my project, and version 6 of react-markdown works fine for now.

I think the next major version of Jest (version 28) will support ESM.

Answer 2

Node is currently treating your .js<\/code> file as CommonJS. You need to tell Node to treat it as an ES module.

Eg:

{
  "name": "passportlegacy",
  "version": "0.1.0",
  "type": "module",
  "private": true,
  "scripts": {
    ...
  }
  ...
}