firebase-api-patch.js

/**
* Update an existing document in a collection.
*/
export async function updateDocumentInCollection({ docID, title, published, modified }) {
  const accessToken = await getAccessToken()

  const response = await (
    await fetch(
      'https://firestore.googleapis.com/v1/projects/<PROJECTIDHERE>/databases/(default)/documents/<COLLECTIONNAME>/<DOCID>?updateMask.fieldPaths=title&updateMask.fieldPaths=published&updateMask.fieldPaths=modified',
      {
        method: 'POST',
        headers: {
          Authorization: 'Bearer ' + accessToken.access_token,
        },
        body: { 
          fields: {
            title: { stringValue: title }, 
            published: { booleanValue: published }, 
            modified: { timestampValue: modified } 
          } 
        }
      }
    )
  ).json()

  return response
}