### What?
Allow the join field to have a configuration `on` relationships inside
of an array, ie `on: 'myArray.myRelationship'`.
### Why?
This is a more powerful and expressive way to use the join field and not
be limited by usage of array data. For example, if you have a roles
array for multinant sites, you could add a join field on the sites to
show who the admins are.
### How?
This fixes the traverseFields function to allow the configuration to
pass sanitization. In addition, the function for querying the drizzle
tables needed to be ehanced.
Additional changes from https://github.com/payloadcms/payload/pull/9995:
- Significantly improves traverseFields and the 'join' case with a raw
query injection pattern, right now it's internal but we could expose it
at some point, for example for querying vectors.
- Fixes potential issues with not passed locale to traverseFields (it
was undefined always)
- Adds an empty array fallback for joins with localized relationships
Fixes #
https://github.com/payloadcms/payload/discussions/9643
---------
Co-authored-by: Because789 <thomas@because789.ch>
Co-authored-by: Sasha <64744993+r1tsuu@users.noreply.github.com>
Add the ability to specify which columns should appear in the
relationship table of a join fields
The new property is in the Join field `admin.defaultColumns` and can be
set to an array of strings containing the field names in the desired
order.
### What?
Adds the ability to set custom validation rules on the root `graphQL`
config property and the ability to define custom complexity on
relationship, join and upload type fields.
### Why?
**Validation Rules**
These give you the option to add your own validation rules. For example,
you may want to prevent introspection queries in production. You can now
do that with the following:
```ts
import { GraphQL } from '@payloadcms/graphql/types'
import { buildConfig } from 'payload'
export default buildConfig({
// ...
graphQL: {
validationRules: (args) => [
NoProductionIntrospection
]
},
// ...
})
const NoProductionIntrospection: GraphQL.ValidationRule = (context) => ({
Field(node) {
if (process.env.NODE_ENV === 'production') {
if (node.name.value === '__schema' || node.name.value === '__type') {
context.reportError(
new GraphQL.GraphQLError(
'GraphQL introspection is not allowed, but the query contained __schema or __type',
{ nodes: [node] }
)
);
}
}
}
})
```
**Custom field complexity**
You can now increase the complexity of a field, this will help users
from running queries that are too expensive. A higher number will make
the `maxComplexity` trigger sooner.
```ts
const fieldWithComplexity = {
name: 'authors',
type: 'relationship',
relationship: 'authors',
graphQL: {
complexity: 100, // highlight-line
}
}
```
### What?
Makes it possible to filter join documents using a `where` added
directly in the config.
### Why?
It makes the join field more powerful for adding contextual meaning to
the documents being returned. For example, maybe you have a
`requiresAction` field that you set and you can have a join that
automatically filters the documents to those that need attention.
### How?
In the database adapter, we merge the requested `where` to the `where`
defined on the field.
On the frontend the results are filtered using the `filterOptions`
property in the component.
Fixes
https://github.com/payloadcms/payload/discussions/8936https://github.com/payloadcms/payload/discussions/8937
---------
Co-authored-by: Sasha <64744993+r1tsuu@users.noreply.github.com>
### What?
Adds a way to prevent creating new documents from the admin UI in a join
field.
### Why?
There are two reasons:
1. You want to disable this any time as a feature of your admin user
experience
2. When creating a new document it is not yet possible to create the
relationship, preventing create is necessary for the workflow to make
sense.
### How?
join field has a new admin property called `allowCreate`, can be set to
false. By default the UI will never allow create when the current
document being edited does not yet have an `id`.
Fixes #
#8892
### Before
Even though the document doesn't have an ID yet, the create buttons are
shown which doesn't actually work.

### After
Initial document creation:

Prevented using `allowCreate: false`

### What?
Allow specifying the defaultSort and defaultLimit to use for populating
a join field
### Why?
It is much easier to set defaults rather than be forced to always call
the join query using the query pattern ("?joins[categories][limit]=0").
### How?
See docs and type changes
1
`import type { Field } from 'payload/types'`
to
`import type { Field } from 'payload'`
2
`import { buildConfig } from 'payload/config'`
to
`import { buildConfig } from 'payload'`
3
```
import { SelectInput, useField } from 'payload/components/forms';
import { useAuth } from 'payload/components/utilities';
```
to
`import { SelectInput, useAuth, useField } from '@payloadcms/ui'`
4
uses `import type` for `import type { CollectionConfig } from 'payload'`
## Description
- Adds a new "join" field type to Payload and is supported by all database adapters
- The UI uses a table view for the new field
- `db-mongodb` changes relationships to be stored as ObjectIDs instead of strings (for now querying works using both types internally to the DB so no data migration should be necessary unless you're querying directly, see breaking changes for details
- Adds a reusable traverseFields utility to Payload to make it easier to work with nested fields, used internally and for plugin maintainers
```ts
export const Categories: CollectionConfig = {
slug: 'categories',
fields: [
{
name: 'relatedPosts',
type: 'join',
collection: 'posts',
on: 'category',
}
]
}
```
BREAKING CHANGES:
All mongodb relationship and upload values will be stored as MongoDB ObjectIDs instead of strings going forward. If you have existing data and you are querying data directly, outside of Payload's APIs, you get different results. For example, a `contains` query will no longer works given a partial ID of a relationship since the ObjectID requires the whole identifier to work.
---------
Co-authored-by: Jacob Fletcher <jacobsfletch@gmail.com>
Co-authored-by: James <james@trbl.design>