Migrating from Sanity version 2 to 3, encountering issue with using the sanity client in a React function.

Good news - you don't need to use the useClient hook for top-level code! The hook is only for React components, but Sanity v3 provides other ways to get a client depending on your context.

For non-React contexts (Structure Builder, Document Actions, etc.)

When you're working in places like the Structure Builder, document actions, initial value templates, or other configuration code, you should use the context.getClient() method instead. These contexts receive a context object that includes a getClient() method:

// In document actions
export function myDocumentAction(props) {
  return {
    label: 'My Action',
    onHandle: () => {
      const client = props.context.getClient({ apiVersion: '2023-05-24' })
      // Use client here
    }
  }
}

// In Structure Builder
export const structure = (S, context) => {
  const client = context.getClient({ apiVersion: '2023-05-24' })
  // Use client to fetch data for your structure
  return S.list()...
}

According to the Document Actions API documentation, the context object includes a getClient function that "returns a configured SanityClient."

For completely standalone code

If you need a client outside of Studio contexts entirely (like in a separate utility file), you can create a standalone client using createClient from @sanity/client:

import { createClient } from '@sanity/client'

const client = createClient({
  projectId: 'your-project-id',
  dataset: 'your-dataset',
  apiVersion: '2023-05-24',
  useCdn: false,
  token: 'your-token' // if needed
})

When to use each approach

• useClient hook: Only inside React components (custom input components, tools, etc.)
• context.getClient(): In Studio configuration contexts (document actions, structure builder, initial values, etc.)
• createClient: For standalone scripts or utilities outside Studio

The key difference from v2 is that the part:@sanity/base/client pattern has been removed. Instead, v3 provides context-appropriate ways to access the client based on where you're working. As mentioned in the useClient documentation, this ensures proper integration with the studio's configured client instance.