It seems from Object.getOwnPropertyNames vs Object.keys, that the main difference between Object.keys() and Object.getOwnPropertyNames() is that the former only returns some of the properties -- those that are enumerable. So I'm wondering for something like an Error object, why it's decided that the properties aren't enumerable. For example:

try {
    let field="XYZ";
    field.a.b.c;
} catch (error) {
    console.log('111', Object.getOwnPropertyNames(error));
    console.log('222', Object.keys(error));
}

Why for example does the Error object not make those properties enumerable? When is a property usually made enumerable?