How to get currently logged in user data inside Sanity schema?

You're absolutely right to be confused - there is indeed a typo in the official documentation on that page. Good catch! Let me clear this up:

The Problem in the Docs

The migration cheat sheet shows:

export function MyComponent {  // ❌ Missing parentheses
  const user = useCurrentUser()
  const {id, name, email, profileImage, provider, roles} = currentUser  // ❌ Wrong variable name
  return <div>JSX</div>
}

There are two errors here:

1. Missing () after MyComponent - it needs to be a proper function declaration
2. Destructuring from currentUser when the variable is actually named user

The Correct Way

Here's how to properly use useCurrentUser() in a React component:

import {useCurrentUser} from 'sanity'

export function MyComponent() {  // ✅ Needs parentheses
  const currentUser = useCurrentUser()  // ✅ Can name it whatever you want
  
  // currentUser can be null, so handle that:
  const {id, name, email, profileImage, provider, roles} = currentUser ?? {}
  
  return <div>JSX</div>
}

Key points:

• export function MyComponent() needs parentheses - this is standard JavaScript function syntax, not a TypeScript shortcut
• The hook returns a user object that you can name anything (user, currentUser, etc.)
• useCurrentUser() returns CurrentUser | null, so use optional chaining (?.) or nullish coalescing (??) to handle the null case

Using Current User in Schema Definitions

Your original code won't work because you cannot use React hooks directly in schema files. Schemas are configuration objects, not React components.

Instead, access currentUser through the context parameter in field-level functions:

export default {
  name: 'myDocument',
  type: 'document',
  fields: [
    {
      name: 'restrictedField',
      type: 'string',
      hidden: ({currentUser}) => {
        // currentUser is available in the context
        return !currentUser?.roles?.some(role => 
          role.name === 'administrator'
        )
      }
    }
  ]
}

The currentUser object in schema contexts has the same shape: {id, name, email, profileImage, provider, roles}.

This is mentioned in the Sanity docs on conditional fields, where currentUser is one of the parameters available to functions like hidden, readOnly, and initialValue.