Order of multiple nested orderBy params

[co-sic]

Is your feature request related to a problem? Please describe.
Lets say if have an entity
Address { city: string; street: string; }
and
Customer { name: string; address: Address; }

and i query the customers entity and want to order by address.city first, then name and then address.street, that is currently not possible as far as i am aware. The orderBy Param would look something like this:

{
  address: {
    city: 'ASC',
  },
  name: 'ASC',
  address: {
    street: 'ASC', 
  },
}

which is not possible because of the duplicate address key.

Describe the solution you'd like
Is there a solution for this which i am not aware of and if not, is there a chance to add something to make this possible? An idea without introducing a breaking change would be to automatically parse keys like "address.city".

{
  'address.city': 'ASC',
  name: 'ASC',
  'address.street': 'ASC', 
}

Or you could optionally allow for an array or object instead of the QueryOrder, where you could specify the order by a number. something like

{
  address: {
    city: ['ASC', 0],
    street: ['ASC', 2], 
  },
  name:  ['ASC', 1],
}

[B4nan]

I'd probably rather go with supporting array too instead of the dot notation, so you can do this:

orderBy: [
  { address: { city: 'ASC' } },
  { name: 'ASC' },
  { address: { street: 'ASC' } },
]

[co-sic]

@B4nan can you estimate how big of a change that would be? If it's not to big and does not involve a lot of knowledge about the codebase, i could go ahead and open a PR. Maybe you could also point me in the direction where i would need to implement this change.

[B4nan]

I guess it could be rather easy, the functional bit will be in QueryBuilder and QueryBuilderHelper, you would also have to adjust the typings a bit. All QB tests are in a single file and they test just the produced query, so they are fast and you can easily verify you did not break anything.

Mostly this method is what you have to change:

https://github.com/mikro-orm/mikro-orm/blob/master/packages/knex/src/query/QueryBuilderHelper.ts#L437

It might as well be as simple as looping over that array instead of using Object.keys() (in general what that method does need to happen for each item in that array).

QB tests are here:

https://github.com/mikro-orm/mikro-orm/blob/master/tests/QueryBuilder.test.ts

[evantrimboli]

Just to tack onto this, as discussed on Slack it would be really cool to support strict typing here too. Thanks!