How to implement a new structure in Sanity.io without crashing the existing site

// deskStructure.js
import S from '@sanity/desk-tool/structure-builder'
import client from 'part:@sanity/base/client'

const { dataset } = client.clientConfig

export default () => {
  if (dataset == 'staging') {
    return S.list()
      .title('My new structure')
      .items([
        S.listItem()
          .title('New title')
          .child(
            S.documentTypeList('myNewType')
              .title('New title')
              .filter('_type == $type')
              .params({type: 'myNewType'})
          ),
      ])
  if (dataset == 'production') {
    return S.list()
    .title('My current structure')
    .items([
      S.listItem()
        .title('Current title')
        .child(
          S.documentTypeList('myType')
            .title('Current title')
            .filter('_type == $type')
            .params({type: 'myType'})
        ),
    ])
  }
}