Support arrayFilter in patch

[GaborTorma]

Please support array filtering in patch method.
https://docs.mongodb.com/manual/reference/operator/update/positional-filtered/

[arfanliaqat]

I think u can already use it just set it as mongoose option

context.params.mongoose = {
    arrayFilters: [{ key: value }],
};

[GaborTorma]

Thanx! I found it, but it's hook.
Is it possible to define it on client side?

[arfanliaqat]

You can use a hack, recommended by maintainers for similar needs

// pass arrayFilters as normal query from client
app.service("comments").patch(_id, 
    { title: "updated title" }, 
    { query: { arrayFilters: [{ key: value }] } }
);


// on server side inside a before patch hook in comments service
context => {
    const { query, mongoose } = context.params;

    if (query.hasOwnProperty("arrayFilters")) {
        // merge existing mongoose options with array filters from client
        context.params.mongoose = { ...mongoose, arrayFilters: query.arrayFilters };
        
        // delete arrayFilters key from query because it is not supposed to be there
        delete context.params.query.arrayFilters;
    }

    return context;
}

You can use it for any other method i.e. create, get, find, or remove as well.

[GaborTorma]

Ohh, thanx! Good solution.
Last question: why not pass it from patch method third parameter (params)?
Like these: patch(id, data, { mongoose: { arrayFilters: [ { key: value } ] } })

[arfanliaqat]

For security reasons maintainers decided not to allow passing all kinda params from client. A few things can only be done on server side. This is one of those cases. However i've seen the above pattern being recommended in several other discussions by maintainers when some param has to be passed from client.

[arfanliaqat]

https://docs.feathersjs.com/api/services.html#params here at the end of params section u can read an important note

Important: For external calls only params.query will be sent 
between the client and server. If not passed, params.query 
will be undefined for internal calls.

So its by design... but u can bypass as per ur need with above pattern

[daffl]

Looks like this is solved. Thanks @arfanliaqat!