Given such a code structure:

const SomeManager = (someParameter) => ({
  addUsedKey(key: string): boolean {
   ...
   usedEntries.push({ key: key });
 }
});

The minifier will fail at { key: key } leaving the value name untouched, so still { key: key }. But the value name is the function parameter, which has been shortened.

I am not sure if this is a general problem with object key-value pairs, or because of the maybe uncommon base structure of the SomeManager, just returning an object with methods.

Btw. also doesn't work, if the parameter/value name is different than "key".

Do you think it's a configuration problem? I set --js-version 2020 only....