Populating Relations in Hooks in next js payload CMS

Sometimes, you may need to populate related data in hooks before saving or fetching a document.

Example: Before Change Hook

import { Payload } from 'payload';

const populateProfile = async ({ req, data }) => {
  const profile = await req.payload.findByID({
    collection: 'profiles',
    id: data.profile,
  });
  return { ...data, profileData: profile };
};

Using Access Control with Relations

Payload CMS allows you to restrict access to related fields using access control functions.

access: ({ req }) => {
  return req.user.role === 'admin';
}

This ensures only admins can access certain related fields.

Using Local API for Relational Queries

In addition to REST and GraphQL, Payload provides a Local API to work with relational data efficiently.

Example: Fetching a User’s Profile Locally

const userWithProfile = await payload.find({
  collection: 'users',
  where: { id: { equals: userId } },
  depth: 2,
});

This ensures that relational data is fully populated within the application without requiring an external API call.

Creating Bidirectional Relations

In some cases, you may want a bidirectional relationship where both collections reference each other.

Example: Linking Users and Organizations

const Organizations: CollectionConfig = {
  slug: 'organizations',
  fields: [
    {
      name: 'members',
      type: 'relationship',
      relationTo: 'users',
      hasMany: true,
    },
  ],
};

This allows an organization to reference multiple users as members.