CRA Failed to minify the code from this file: mobx.module.js:23

[ashconnell]

This related issue was fixed but it looks like it might be back in 5.0.0

ashconnell$ yarn build
yarn run v1.7.0
$ react-scripts build
Creating an optimized production build...
Failed to compile.

Failed to minify the code from this file:

        ./node_modules/mobx/lib/mobx.module.js:23

Read more here: http://bit.ly/2tRViJ9

error Command failed with exit code 1.

Quickest way to reproduce is to git clone this repo and run yarn && yarn build

[mweststrate]

I have some idea what is happening here and will investigate further on monday, but first a double check, you are using the latest version of CRA?

[feat7]

I got into same issue today. After a lot of research and different attempts to solve the error, everything went in vain.
I am using custom-react-scripts with create-react-app
I managed to solve this issue by downgrading to mobx@4.3.1 (any version of 4 is working fine)
Hope this temporarily fix the issue.

[ashconnell]

@mweststrate i used npx create-react-app ... which i believe always uses the latest version of a package,

You can get a minimal reproduction with this:

npx create-react-app mobx-5-cra-build
cd mobx-5-cra-build
yarn add mobx
echo "import { observable } from 'mobx'" > src/index.js
yarn build

I've spent an hour looking into this but i'm not super familiar with rollup and how CRA builds work

[mweststrate]

Thanks for the minimal reproduction @ashconnell.

I reverted MobX back to using ES5 only. That should solve thte issue. Released as 5.0.1

[mweststrate]

Pro tip, the default build is now ES5, but you can still use the smaller and faster build by setting up an alias. Webpack example: resolve: { alias: { mobx: __dirname + "/node_modules/mobx/lib/mobx.es6.js" }}