Object.assign et al are not polyfilled

[conatus]

Hi all,

Thanks for your wonderful work on this.

When testing a React app using create-react-app on a old version of mobile Safari I noticed that Object.assign was failing.

I looked and saw that polyfill support is turned off on the configuration of babel-plugin-transform-runtime https://github.com/facebookincubator/create-react-app/blob/master/config/babel.prod.js#L33-L37

I worked around this by, for the moment, slightly inefficiently manually adding babel-polyfill and using the more "traditional" import 'babel-polyfill'; at the root of the application to include core-js polyfills.

Seems that if the goal is zero configuration setup this is going to be a gotcha for more than a few folks. Unsure if the best approach is to simply turn on the polyfill in babel-plugin-transform-runtime as the documentation seems to suggest this is not the intent of this transformation to supplement native methods like Object.assign.

[conatus]

@gaearon @vjeux further to Twitter convo.

[gaearon]

I probably wouldn’t turn on the whole runtime (it’s pretty aggressive and brings in half of core-js).

However Object.assign() seems reasonably since we provide spread operator anyway, and we also use object-assign inside of React itself.

So we’ll probably just do that.

[mnemanja]

Hi @gaearon,
I'm at the script version 1.0.12 and IE11 reports this as a problem.
Am I missing some implementation detail? Do I need to import it manually or something like that?

Cheers,
Nemanja

[dcp12345678]

I get exactly the same problem as mnemanja.

Version Info:
C:\src\sandbox\react\my-app>create-react-app --version
1.4.0

[dcp12345678]

Note: adding this to index.html seems to resolve the create-react-app bug with ie11, but this doesn't feel like a good solution:
<script src="//cdn.polyfill.io/v2/polyfill.min.js"></script>

[Timer]

Can you please open a new issue? It's hard to track in old, closed issues.

[dcp12345678]

Timer, here you go: #3034