Ports code does not support Async/Await

[Max Wolff]

Adding an async function to index.js such as

const f = async () => {
	await new Promise(r => setTimeout(r, 2000));
}

Causes elm-app start to fail with

./src/index.js
Module not found: Can't resolve '@babel/runtime/regenerator'

Node 14.9, 1.22, OS X, Chrome,

which elm-app => node/v10.18.1/bin/elm-app
yarn doesnt have a ls for global afaik

Hacking around this by transpiling w babel manually, npx babel src/index2.js --out-file src/index.js --plugins async-to-promises

I suspect adding some babel plugins in the webpack config somewhere around here would do it.

Another clue: https://babeljs.io/docs/en/babel-plugin-transform-runtime#technical-details

The transform-runtime transformer plugin does three things:

Automatically requires @babel/runtime/regenerator when you use generators/async functions (toggleable with the regenerator option).

Though it looks like transform-runtime is installed and regenerator should be part of it.

[Marc Walter]

I was able to get rid of this error by specifying a browserslist of current browsers inside package.json.

But if you want your app to work on old browsers that won't help you I'm afraid.

[Max Wolff]

thx, at some point we gotta leave those old browsers behind :)

[Matt Hughes]

I just ran into this as well. Is setting a browerlist in each individual project the right solution? Can that be added to create-elm-app itself, or is there a better solution to this?