Numeric Separators not supported if used with React

[clickwithclark]

I'm submitting a bug report

Webpack Version:
4.44.2

Babel Core Version:
"7.16.0",

Babel Loader Version:
5.4.x/6.2.x

Please tell us about your environment:
Windows 10

Current behaviour:
Numeric Separators not working with React
It detects underscores as an identifier

Expected/desired behaviour:
10_000 should be seen as 10000
instead is seen as 10 and _000

Uncertain of how to get the configuration,
Building a module works fine on its own with webpack.
but using the module in a React Application throws a failed to compile error

for example : One of the functions in my module is written as :

export function waitForElement(
  selector,
  checkFrequencyInMs = 500,
  timeoutInMs = 10_000
......
) {

When I try to use it in a React App :

Sorry if the information is not sufficient. If it needs to be placed somewhere else instead please let me know.

Everything works when I removed the underscore.

[JLHwung]

The error is thrown from acorn because webpack 4 does not support ES2021. You can upgrade to webpack 5.