Support ES Modules in @babel/preset-typescript

[LandonSchropp]

💻

• Would you like to work on this feature?

What problem are you trying to solve?

Apologies if this is captured elsewhere. I'm trying to sort out all of the moving parts with configuring Babel/TypeScript, so I may have missed something.

I'm setting up a TypeScript Node.js project, and I'd like to be able to do the following:

• Use TypeScript.
• Use the import/export syntax in my files.
• Use top-level await (requires "type": "module" in package.json)
• Use Jest (requires Babel)

Describe the solution you'd like

Ideally, I'd be able to have one TypeScript configuration and use that for everything, including running my project, type checking, and running my tests. Here's what I'd expect the configuration to look like:

// babel.config.json
{
  "presets": [
    "@babel/preset-env",
    "@babel/preset-typescript"
  ]
}

// package.json
{
  "type": "module",
  ...
}

Describe alternatives you've considered

Prior to adding Jest as a requirement, I was using ts-node. However, with Jest, I need to be able to use Babel. Ideally, I'd be able to use the same configuration and tools for everything, to ensure the code works consistently.

Documentation, Adoption, Migration Strategy

No response

[babel-bot]

Hey @LandonSchropp! We really appreciate you taking the time to report an issue. The collaborators on this project attempt to help as many people as possible, but we're a limited number of volunteers, so it's possible this won't be addressed swiftly.

If you need any help, or just have general Babel or JavaScript questions, we have a vibrant Slack community that typically always has someone willing to help. You can sign-up here for an invite.

[nicolo-ribaudo]

Hi! Sorry this issue didn't get noticed 🙂

I think all the four requirements you have should work, but you might need to tell Babel not to compile ESM to CJS:

{
  "presets": [
    ["@babel/preset-env", { "modules": false }],
    "@babel/preset-typescript"
  ]
}

However, you will need to compile your files ahead of time (using @babel/cli): Babel does not support running "at runtime" yet like ts-node when using native ESM, because Node.js doesn't have a stable ESM loader API yet.

[LandonSchropp]

Not a problem at all! Thanks for the reply. 🙂

Ah, I wasn't aware of the modules setting in preset-env. That's really helpful to know.

Babel does not support running "at runtime" yet like ts-node when using native ESM, because Node.js doesn't have a stable ESM loader API yet.

That makes sense. Fingers crossed that lands sometime soon.

Thanks!