[Bug]: "??=" operator does not work properly in the mobile application

[KyrieChen]

System Info

rspack 0.7.0
device：OPPO Find X
ColorOS：v7.1
Android version：10
Webview: Mozilla/5.0 (Linux; Android 10; PAFM00 Build/QKQ1.191008.001; wv) AppleWebKit/537.36 (KHTML, like Gecko) Version/4.0 Chrome/77.0.3865.92 Mobile Safari/537.36

Details

In our project, we found that errors occur in the webview due to the use of the ??= operator without proper compatibility handling. The error is shown in the image below.

During the troubleshooting process, we found that the code is located here.

rspack/packages/rspack/src/container/default.runtime.js

Line 19 in c2488a6

obj[key] ??= [];

This issue only appeared after we upgraded to rspack version v0.7.0.

Reproduce link

No response

Reproduce Steps

The issue can be reproduced immediately using the code from the official website with mf.

[ckken]

+1

[LingyuCoder]

cc @ahabhgk , this a .js script in @rspack/core, should it transform by tsc?

[ckken]

Is it possible to provide an implementation option?

[ahabhgk]

#6672 The fix will be released in v0.7.1, in v0.7.1 if you have swc-loader/babel-loader to transform your js syntax, then the module federation runtime will also be transformed by your swc-loader/babel-loader

[ahabhgk]

For example: https://github.com/web-infra-dev/rspack/pull/6672/files#diff-23b4fa030250efc8c22bb3097281f4a66811a42c7d8dc2048a17fb3bbd6480bf