### What?
Adds `defaultPopulate` property to collection config that allows to
specify which fields to select when the collection is populated from
another document.
```ts
import type { CollectionConfig } from 'payload'
// The TSlug generic can be passed to have type safety for `defaultPopulate`.
// If avoided, the `defaultPopulate` type resolves to `SelectType`.
export const Pages: CollectionConfig<'pages'> = {
slug: 'pages',
// I need only slug, NOT the WHOLE CONTENT!
defaultPopulate: {
slug: true,
},
fields: [
{
name: 'slug',
type: 'text',
required: true,
},
],
}
```
### Why?
This is essential for example in case of links. You don't need the whole
document, which can contain large data but only the `slug`.
### How?
Implements `defaultPopulate` when populating relationships, including
inside of lexical / slate rich text fields.
Adds `select` which is used to specify the field projection for local
and rest API calls. This is available as an optimization to reduce the
payload's of requests and make the database queries more efficient.
Includes:
- [x] generate types for the `select` property
- [x] infer the return type by `select` with 2 modes - include (`field:
true`) and exclude (`field: false`)
- [x] lots of integration tests, including deep fields / localization
etc
- [x] implement the property in db adapters
- [x] implement the property in the local api for most operations
- [x] implement the property in the rest api
- [x] docs
---------
Co-authored-by: Dan Ribbens <dan.ribbens@gmail.com>
