text: 
  import {
    Doc, UpdateDecoderV1, UpdateDecoderV2, UpdateEncoderV1, UpdateEncoderV2, StructStore, Transaction, Item // eslint-disable-line
  } from '../internals.js'
  
  import * as error from 'lib0/error.js'
  
  /**
   * @private
   */
  export class ContentDoc {
    /**
     * @param {Doc} doc
     */
    constructor (doc) {
      if (doc._item) {
        console.error('This document was already integrated as a sub-document. You should create a second instance instead with the same guid.')
      }
      /**
       * @type {Doc}
       */
      this.doc = doc
      /**
       * @type {any}
       */
      const opts = {}
      this.opts = opts
      if (!doc.gc) {
        opts.gc = false
      }
      if (doc.autoLoad) {
        opts.autoLoad = true
      }
      if (doc.meta !== null) {
        opts.meta = doc.meta
      }
    }
  
    /**
     * @return {number}
     */
    getLength () {
      return 1
    }
  
    /**
     * @return {Array<any>}
     */
    getContent () {
      return [this.doc]
    }
  
    /**
     * @return {boolean}
     */
    isCountable () {
      return true
    }
  
    /**
     * @return {ContentDoc}
     */
    copy () {
      return new ContentDoc(this.doc)
    }
  
    /**
     * @param {number} offset
     * @return {ContentDoc}
     */
    splice (offset) {
      throw error.methodUnimplemented()
    }
  
    /**
     * @param {ContentDoc} right
     * @return {boolean}
     */
    mergeWith (right) {
      return false
    }
  
    /**
     * @param {Transaction} transaction
     * @param {Item} item
     */
    integrate (transaction, item) {
      // this needs to be reflected in doc.destroy as well
      this.doc._item = item
      transaction.subdocsAdded.add(this.doc)
      if (this.doc.shouldLoad) {
        transaction.subdocsLoaded.add(this.doc)
      }
    }
  
    /**
     * @param {Transaction} transaction
     */
    delete (transaction) {
      if (transaction.subdocsAdded.has(this.doc)) {
        transaction.subdocsAdded.delete(this.doc)
      } else {
        transaction.subdocsRemoved.add(this.doc)
      }
    }
  
    /**
     * @param {StructStore} store
     */
    gc (store) { }
  
    /**
     * @param {UpdateEncoderV1 | UpdateEncoderV2} encoder
     * @param {number} offset
     */
    write (encoder, offset) {
      encoder.writeString(this.doc.guid)
      encoder.writeAny(this.opts)
    }
  
    /**
     * @return {number}
     */
    getRef () {
      return 9
    }
  }
  
  /**
   * @private
   *
   * @param {UpdateDecoderV1 | UpdateDecoderV2} decoder
   * @return {ContentDoc}
   */
  export const readContentDoc = decoder => new ContentDoc(new Doc({ guid: decoder.readString(), ...decoder.readAny() }))
  