Initial value template with current user

// initialValueTemplates.js

import T from '@sanity/base/initial-value-template-builder'
import userStore from 'part:@sanity/base/user'

export default {
  ...T.defaults,
  T.template({
    id: 'newsStory',
    title: 'News story',
    schemaType: 'newsStory',
    value: async () => {
      const {name, id} = await userStore.getUser('me')
      return {
        author: {
          name,
          id,
          _type: 'author'
        },
      }
    }
  })
}

/*
Shape of the user object from userStore.getUser('me'):
{
  "id": "pCuO6i54C",
  "projectId": "3do82whm",
  "displayName": "Your name",
  "familyName": "Your family name",
  "givenName": "Your given name",
  "middleName": "Your middle name",
  "imageUrl": "<your-avatar-image>",
  "createdAt": "2018-04-02T14:21:46.688Z",
  "updatedAt": "2020-12-30T08:21:25.286Z",
  "isCurrentUser": true
}
*/

export default {
  name: 'author',
  type: 'object',
  title: 'Author',
  fields: [
    {
      name: 'name',
      type: 'string',
      title: 'Full name'
    },
    {
      name: 'id',
      type: 'string',
      title: 'User ID',
      readOnly: true,
      description: `This author's user ID. Used for workflow scripts and similar.`
    }
  ]
}