Import error with CRA v2 (webpack 4)

[capi1O]

description

Using create-react-app v2, an error is thrown on start : "Can't import the named export 'AUTH_CHECK' from non EcmaScript module"

workaround

add type: 'javascript/auto', in module section of webpack.config.js.

explanation

modules with mjs extension are now treated differently by webpack 4 :

Files ending with .mjs are parsed as javascript/esm, a stricter mode. This mode does not allow to import CJS modules like ESM ones.

source : apollographql/react-apollo#1737

Similar issue with react-appolo :

In react-apollo, react-apollo.browser.umd.js is evaluated by webpack as javascript/auto (webpack 3 default mode). It is a loose mode to preserve compatibility that support both CJS and ESM within the same file. When webpack parses require("./ApolloProvider") it will look at ./ApolloProvider.mjs first.

While this issue looks like a webpack one, it is not: react-apollo should correctly import non-ESM dependencies, in this case react.

version

react-admin-firebase v0.5.1

[benwinding]

Hi @monkeydri,
Thanks for reporting this issue. Sorry I don't really understand this, would you be able to explain the issue in a little more detail? Or make a pull request to fix this?
Cheers,
Ben

[capi1O]

Well as I understood it now webpack 4 treats modules with .mjs extension differently, and as a result only default exports are allowed.

This is the error on standard CRA (v2) : https://codesandbox.io/s/723r5p804q

Will try to submit a PR this week end

[jevin]

@monkeydri, any update on the PR?

[benwinding]

I will also take a look at this later today too...

…

On Tue., 7 May 2019, 3:41 am jevin, ***@***.***> wrote: @monkeydri <https://github.com/monkeydri>, any update on the PR? — You are receiving this because you modified the open/close state. Reply to this email directly, view it on GitHub <#14 (comment)>, or mute the thread <https://github.com/notifications/unsubscribe-auth/ACZ4TPVWLAO2VUM73IXHOF3PUBYEZANCNFSM4HIK7ZYQ> .

[jevin]

Thanks guys!

[benwinding]

Fixed the issue, please upgrade to version 0.5.3 and please advise if there's any problems.

Issue

The .mjs reference has been removed, so create-react-app won't look for it anymore.

Commit: #0bccf9b

Thanks everyone for reporting the issue! 👍
Ben