Improve defaultValue types and allow relationship to accept more than a function

[evelynhathaway]

Documentation Issue

The relationship field documentation doesn't provide a description of the type or what data should be included for the defaultValue option.

Improving the TypeScript types for CollectionConfig and the documentation could help new users.

Additional Details

I ran into errors while trying to add a default value to a relationship field

There were 1 errors validating your Payload config
Collection "posts" > Field "category" > "value" does not match any of the allowed types

I had to dive into the source code to find it only accepts a function

payload/src/fields/config/schema.ts

Lines 313 to 315 in 934b443

	defaultValue: joi.alternatives().try(
	joi.func(),
	),

Before I found that, I tried using:

• id as a string
• name as a string with useAsTitle: 'name' on the related collection
• Array of ids
• Object that implements type ValueWithRelation
• Array of ValueWithRelation objects

[jmikrut]

Hey @evelynhathaway — this is all good stuff!

I agree with everything that you're saying. I believe the reason we restricted the relationship field to accept only a function for defaultValue is that generally you need to know the ID of the documents created before you can set the defaultValue accordingly, and the ID would typically be fetched as a result within a function, but I guess this doesn't necessarily need to be the case. We can probably remove that restriction.

In addition, I think that we can improve the types here so that the defaultValue type is inferred based on the field type.

Going to add this to our roadmap priority 2 and convert it to a discussion. This would also be a great PR if you are looking to contribute! Otherwise the Payload team will definitely address this.

Thank you!!

[evelynhathaway]

That sounds great!

the ID would typically be fetched as a result within a function

How could that be done? It looks like payload.find would be a great solution, but the local API appears to be unavailable. I think an example would be great to document.

---

/src/collections/Posts.ts

import payload from 'payload';
import { CollectionConfig } from 'payload/types';

const Posts: CollectionConfig = {
  slug: 'posts',
  fields: [
    {
      name: 'category',
      type: 'relationship',
      relationTo: 'categories',
      defaultValue: async () => {
        const categoryDocuments = await payload.find({
          collection: 'categories',
          where: {
            name: {
              equals: "News",
            },
          },
        });
        return categoryDocuments.docs[0];
      },
    },
  ],
};

export default Posts;

Error in DevTools

Uncaught (in promise) TypeError: payload__WEBPACK_IMPORTED_MODULE_0__.default.find is not a function

Snippet of /src/collections/Posts.ts in the Webpack Bundle

var payload__WEBPACK_IMPORTED_MODULE_0__ = __webpack_require__(/*! payload */
	"./node_modules/payload/dist/webpack/mocks/emptyModule.js");

const Posts = {
// [...]

[jmikrut]

You'd need to use fetch, because the defaultValue function is run in the browser as well as the server. So fetch is the safest way for sure.

[evelynhathaway]

Oh right, of course! This worked for me.

      // [...]
      defaultValue: async () => {
        const response = await fetch("/api/categories?limit=1&where[name][equals]=News");
        const data: PaginatedDocs<{ id: string }> = await response.json();
        const [newsCategory] = data.docs;
        return newsCategory?.id;
      },
      // [...]

[johannesschaffer]

The documentation also doesn't explain how to set a defaultValue for an array

[ssyberg]

Oh man I just lost a few hours to this, let's update the docs!

[sykire]

I'm having problems with this:

{
      filterOptions: ({ data }) => {
        return {
          spaces: {
            contains: data?.space?.id
          }
        }
      },
      name: "author",
      type: "relationship",
      relationTo: "users",
      admin: {
        position: "sidebar",
        allowCreate: false
      },
      defaultValue: ({ user }) => [user.id],
      hasMany: true
    },

[JavierBrooktec]

For anyone wondering how to pass default data to an array, debug it with the admin condition

admin: {
 condition: (data, siblingData, { user }) => {
  console.log(data);
  return true;
  },
},

and pass a similar structure to your default value