Converting portable text to plaintext in Sanity.io using a script

/* eslint-disable no-console */
import sanityClient from 'part:@sanity/base/client'
const client = sanityClient.withConfig({ apiVersion: '2023-03-02' })

const fetchDocuments = () => client.fetch(`*[_type == 'post' && plaintext != pt::text(body)]{_id, _rev, plaintext, 'body': pt::text(body)}`)

const buildPatches = docs => (
	docs.map(doc => ({
		id: doc._id,
		patch: {
			set: {
				plaintext: doc.body
			},
			ifRevisionID: doc._rev,
		}
	}))
)

const createTransaction = patches =>
  patches.reduce((tx, patch) => tx.patch(patch.id, patch.patch), client.transaction())

const commitTransaction = tx => tx.commit()

const editNextBatch = async () => {
  const documents = await fetchDocuments()
  const patches = buildPatches(documents)

  if (patches.length === 0) {
    console.log('No more documents to edit!')
    return null
  }

  console.log(
    `Editing batch:\n %s`,
    patches.map(patch => `${patch.id} => ${JSON.stringify(patch.patch)}`).join('\n')
  )
  const transaction = createTransaction(patches)
  await commitTransaction(transaction)
  return editNextBatch()
}

editNextBatch().catch(err => {
  console.error(err)
  process.exit(1)
})

sanity exec scripts/scriptName.js --with-user-token