MongoDB shell // Invalidate email in collections

script.js

db.getCollectionNames().map(function(collection) {
  var hasEmailField = db[collection].count({ email: { $exists: true }})
  if ( !hasEmailField )   return "no email field in : " + collection
  db[collection].find({}).map(function(item) {
    db[collection].update(
      { _id: item._id },
      {
        $set: {
          email: item.email.replace(
            /@.*\..*/,
            '@INVALID_' + Date.now() + '_INVALID.fake'
          )
        }
      }
    );
  });
  return "cleared email from: " + collection
});