Uncaught TypeError: Super expression must either be null or a function, not undefined

[danjumamilhaus]

Getting error this in a production environment, while local dev works without issues.
Using react-dates 18.2.0 18.2.1

Uncaught TypeError: Super expression must either be null or a function, not undefined
    at withStyles.js:44
    at withStyles.js:44
    at withStyles.js:158
    at Object.<anonymous> (CalendarDay.js:276)
    at o (bootstrap:78)
    at Object.<anonymous> (index.js:207)
    at o (bootstrap:78)
    at Object.<anonymous> (index.js:2)
    at o (bootstrap:78)
    at Object.<anonymous> (sn.hd.product.js:53)

[ljharb]

In what browser? There’s a known issue in 18.2.0 in IE 9-11, due to a bug in babel around inheritance hierarchies. 18.2.1 fixes it, and 18.2.2 will fix #1455.

[danjumamilhaus]

Chrome v70. Also an issue in v69. Happening for other users in Chrome, not sure their versions. Error is happening in Firefox v63 as well.

[ljharb]

And to confirm, you’re not running node_modules through babel?

[danjumamilhaus]

It's excluded from babel.

[danjumamilhaus]

So, I seem to have solved this in our case at least.

In our production webpack task, we are using the uglify-webpackjs-plugin.

Adding the lines:

uglifyOptions: {
  keep_fnames: true
},

keep this error from happening in that environment.

Possibly some food for thought on why this issue is happening in the future.

[ljharb]

Definitely that’s a good change to make; but it shouldn’t be affecting this. It might be a bug in uglify.

[danjumamilhaus]

Unfortunately it's not a viable change since we would like to not turn this on across the site. It seems to only be an issue within this library, specifically within CalendarDay.js.

[ljharb]

Can you try 18.2.1?

[danjumamilhaus]

Still an issue in 18.2.1

[danjumamilhaus]

In this case, the superClass React.PureComponent is undefined.

[Dodie324]

We're also experiencing this error in our application code base.

[ljharb]

@danjumamilhaus what version of React are you using?

[danjumamilhaus]

Ultimately, upgrading uglifyjs-webpack-plugin to v2.0.1 from v1.2.7 solved this issue. Found the info I needed starting here: facebook/react#13987 (comment) in case some lone traveler is interested.

[danjumamilhaus]

Tested using React v16.4.1

[muganwas]

I had this error, turns out i had misspelled Component, i had written Class blabla extends React.Compnent.