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Update to core-js@3 #6769

merged 4 commits into from Apr 14, 2019


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commented Apr 7, 2019

This is a breaking change to our 3.0 alpha that deprecates the @babel/polyfill feature in favor of the recommended approach from the babel team as part of the babel 7.4.0 release. This adds a new react-app-polyfill/stable module that can be imported from src/index.js which will include polyfills for stable language features, and integrates nicely with @babel/preset-env which uses browserslist to only include polyfills for the target browsers.

Some more relevant info on this change:

Outstanding questions:

  • In the corejs@2 migration guide it says
    • If you are using @babel/plugin-transform-runtime, you need to use the corejs: 3 option

    • We currently have corejs: false so my sense is we can ignore this, but it would be helpful if someone with more knowledge of this plugin could chime in

@ianschmitz ianschmitz added this to the 3.0 milestone Apr 7, 2019

@ianschmitz ianschmitz added this to In progress in v3 via automation Apr 7, 2019


mrmckeb approved these changes Apr 7, 2019

Update packages/react-app-polyfill/
Co-Authored-By: ianschmitz <>

@ianschmitz ianschmitz merged commit bffc296 into facebook:master Apr 14, 2019

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v3 automation moved this from In progress to Done Apr 14, 2019

@ianschmitz ianschmitz deleted the ianschmitz:corejs-update branch Apr 14, 2019


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commented Apr 15, 2019

There is no react-app-polyfill/stable in the published version.

"react-app-polyfill": "1.0.0-next.b0cbf2ca",
"react-scripts": "3.0.0-next.b0cbf2ca",

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commented Apr 15, 2019

This was just merged in recently @brunolemos. We will publish a new alpha shortly.

@iansu iansu referenced this pull request Apr 17, 2019

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