This will make it possible for packages dependant on graphql to in turn do the same for their consumers, without encountering babel/babel#7294.

Node.js with --experimental-modules can run ESM in .mjs files.

Essentially, package.json needs to go from this:

{
  "main": "index.js",
  "module": "module/index.js"
}

To this:

{
  "main": "index",
  "module": "index.mjs"
}

Sibling index.js (CJS) and index.mjs (ESM) files need to be published. Node.js will load the relevant file, looking up .mjs before .js for main if --experimental-modules is enabled.