You can use
includeas well to make the opposite[to exclude] exception (but you usually won’t need this option)
Include will not make an “exception” to test. Include condition won’t override test condition (unlike exclude) — both test and&& include must be matched.
So docs recommend to use test to provide regex(s) to match filenames or extensions, while include should be used together with test to provide string(path) to, presumably, your source folder. Note that path must be absolute, cause string condition is matched when source’s path begins with given string.
this way all .jsx files only inside your “app” directory will be used. Nothing else will be “mangled”