The `$pushAll` operator is no longer supported in Mongo 3.6.2 (or any newer versions from 3.6.x+).
You can either downgrade to a 3.4.x version.
Or you can use `usePushEach: true` in such a form
`new mongoose.Schema({
username: String
}, {
usePushEach: true
});`
The `$pushAll` operator is no longer supported in Mongo 3.6.2 (or any newer versions from 3.6.x+).
You can do the following:
- add the [`usePushEach: true` option the Schema definition][1].
- downgrade to Mongo 3.4.11(or any 3.4.x version)
[1]: https://medium.com/@stefanledin/how-to-solve-the-unknown-modifier-pushall-error-in-mongoose-d631489f85c0
