# React 16 error on after build

**URL:** <https://devforum.zoom.us/t/react-16-error-on-after-build/5693>\
**Category:** Web\
**Created:** [August 27, 2019, 4:27am UTC](https://devforum.zoom.us/t/react-16-error-on-after-build/5693 "2019-08-27T04:27:26Z")\
**Posts on this page:** 8\
**Page:** 1

<div class="post-metadata">

**Author:** ![nezto](https://sea2.discourse-cdn.com/flex016/user_avatar/devforum.zoom.us/nezto/32/1668_2.png) [@nezto](https://devforum.zoom.us/u/nezto)\
**Post date:** [August 27, 2019, 4:27am UTC](https://devforum.zoom.us/t/react-16-error-on-after-build/5693/1 "2019-08-27T04:27:26Z")

</div>

I have a create-react-app, in development it’s working fine, but on production trigger this error

backend.js:1 TypeError: Super expression must either be null or a function, not undefined  
at zoomus-jssdk.umd.min.js:38208  
at zoomus-jssdk.umd.min.js:38207  
at Object.e.exports (zoomus-jssdk.umd.min.js:38193)  
at t (zoomus-jssdk.umd.min.js:38146)  
at e.exports (zoomus-jssdk.umd.min.js:38150)  
at Object.e.exports (zoomus-jssdk.umd.min.js:38138)  
at n (zoomus-jssdk.umd.min.js:15)  
at Object.e.exports (zoomus-jssdk.umd.min.js:10826)  
at n (zoomus-jssdk.umd.min.js:15)  
at Object.e.exports (zoomus-jssdk.umd.min.js:34240)

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<div class="post-metadata">

**Author:** ![tommy](https://sea2.discourse-cdn.com/flex016/user_avatar/devforum.zoom.us/tommy/32/72769_2.png) [@tommy](https://devforum.zoom.us/u/tommy)\
**Post date:** [August 27, 2019, 3:47pm UTC](https://devforum.zoom.us/t/react-16-error-on-after-build/5693/2 "2019-08-27T15:47:23Z")

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Hey @nezto,

Can you post your code here so we can debug?

Thanks,  
Tommy

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<div class="post-metadata">

**Author:** ![nezto](https://sea2.discourse-cdn.com/flex016/user_avatar/devforum.zoom.us/nezto/32/1668_2.png) [@nezto](https://devforum.zoom.us/u/nezto)\
**Post date:** [August 27, 2019, 8:37pm UTC](https://devforum.zoom.us/t/react-16-error-on-after-build/5693/3 "2019-08-27T20:37:33Z")

</div>

Hi, this is my code:

```auto
import React from "react";
import { connect } from "react-redux";
import { ZoomMtg } from "zoomus-jssdk";
import Cliente from "../../api/cliente";
import token from "../../helpers/token";

const API_KEY = "";

const meetConfig = {
  apiKey: API_KEY,
  meetingNumber:,
  userName: "",
  passWord: "",
  leaveUrl: window.origin,
  role: 0
};

class Page extends React.Component {
  componentDidMount() {
    window.$.i18n.reload("es-ES");

    ZoomMtg.setZoomJSLib("https://source.zoom.us/1.5.0/lib", "/av");
    ZoomMtg.preLoadWasm();
    ZoomMtg.prepareJssdk();

    Cliente.setBearerToken(token())
      .getCliente()
      .post("zoom/signature", {
        meetConfig
      })
      .then(res => {
        ZoomMtg.init({
          debug: false,
          leaveUrl: window.origin,
          screenShare: false,
          disableInvite: true,
          disableCallOut: true,
          showPureSharingContent: false,
          success() {
            ZoomMtg.join({
              meetingNumber: meetConfig.meetingNumber,
              userName: meetConfig.userName,
              signature: res.data.signature,
              apiKey: meetConfig.apiKey,
              // userEmail: "email@gmail.com",
              passWord: meetConfig.passWord,
              success() {
                console.log("join meeting success");
              },
              error(res) {
                console.log(res);
              }
            });
          },
          error(res) {}
        });
      })
      .catch(err => {});
  }

  componentWillUnmount() {
    ZoomMtg.leaveMeeting({});
  }

  render() {
    return <>Zoom</>;
  }
}

const mapStateToProps = state => {
  return {
    user: state.userInfo,
    cc_user: state.cc_user,
    cc_chat: state.cc_chat,
    cc_message: state.cc_message,
    cc_call: state.cc_call
  };
};

export default connect(mapStateToProps)(Page);

```

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<div class="post-metadata">

**Author:** ![nezto](https://sea2.discourse-cdn.com/flex016/user_avatar/devforum.zoom.us/nezto/32/1668_2.png) [@nezto](https://devforum.zoom.us/u/nezto)\
**Post date:** [August 28, 2019, 2:23pm UTC](https://devforum.zoom.us/t/react-16-error-on-after-build/5693/5 "2019-08-28T14:23:16Z")

</div>

Hi bro, I solved this problem with a configuration in config-overrides.js

config.optimization = {  
minimizer: [  
new UglifyJsPlugin({  
uglifyOptions: { keep\_fnames: true } //this line is 💪  
})  
]  
};

Thanks

---

<div class="post-metadata">

**Author:** ![tommy](https://sea2.discourse-cdn.com/flex016/user_avatar/devforum.zoom.us/tommy/32/72769_2.png) [@tommy](https://devforum.zoom.us/u/tommy)\
**Post date:** [August 28, 2019, 6:45pm UTC](https://devforum.zoom.us/t/react-16-error-on-after-build/5693/7 "2019-08-28T18:45:46Z")

</div>

Hey @nezto,

Thanks for posting your solution! I am glad you figured it out!

-Tommy

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<div class="post-metadata">

**Author:** ![vincent.engelmann1](https://sea2.discourse-cdn.com/flex016/user_avatar/devforum.zoom.us/vincent.engelmann1/32/975_2.png) [@vincent.engelmann1](https://devforum.zoom.us/u/vincent.engelmann1)\
**Post date:** [November 5, 2019, 5:37pm UTC](https://devforum.zoom.us/t/react-16-error-on-after-build/5693/8 "2019-11-05T17:37:13Z")

</div>

Two confusing bits to this

1. newer create-react-app webpack configs might be using TerserPlugin instead of UglifyJsPlugin
2. using `keep_fnames: true` (which also applies to TerserPlugin) might not be enough to prevent mangling zoom sdk’s code. In my case I had to remove TerserPlugin alltogether and will need to look for an alternative or look into config options more deeply.

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<div class="post-metadata">

**Author:** ![tommy](https://sea2.discourse-cdn.com/flex016/user_avatar/devforum.zoom.us/tommy/32/72769_2.png) [@tommy](https://devforum.zoom.us/u/tommy)\
**Post date:** [November 5, 2019, 9:51pm UTC](https://devforum.zoom.us/t/react-16-error-on-after-build/5693/9 "2019-11-05T21:51:30Z")

</div>

Hey @vincent.engelmann1, thanks for posting and using Zoom!

Were you able to resolve the issue? 🙂

Thanks,  
Tommy

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<div class="post-metadata">

**Author:** ![DeveloperBot](https://sea2.discourse-cdn.com/flex016/user_avatar/devforum.zoom.us/developerbot/32/12632_2.png) [@DeveloperBot](https://devforum.zoom.us/u/DeveloperBot)\
**Post date:** [August 21, 2020, 6:59pm UTC](https://devforum.zoom.us/t/react-16-error-on-after-build/5693/10 "2020-08-21T18:59:01Z")

</div>

Closed on August 21, 2020, 6:59pm UTC