Function testAttributions

tests/delta.tests.js:159–195

 * @param {t.TestCase} _tc
 */
export const testAttributions = _tc => {
  const ydocV1 = new Y.Doc()
  const ytypeV1 = ydocV1.get('txt')
  ytypeV1.applyDelta(delta.create().insert('hello world'))
  // create a new version with updated content
  const ydoc = new Y.Doc()
  Y.applyUpdate(ydoc, Y.encodeStateAsUpdate(ydocV1))
  const ytype = ydoc.get('txt')
  // delete " world" and insert exclamation mark "!".
  ytype.applyDelta(delta.create().retain(5).delete(6).insert('!'))
  const am = Y.createAttributionManagerFromDiff(ydocV1, ydoc)
  // get the attributed differences
  const attributedContent = ytype.toDelta(am)
  console.log('attributed content', attributedContent.toJSON())
  t.assert(attributedContent.equals(delta.create().insert('hello').insert(' world', null, { delete: [] }).insert('!', null, { insert: [] })))
  // for editor bindings, it is also necessary to observe changes and get the attributed changes
  ytype.observe(event => {
    const attributedChange = event.getDelta(am)
    console.log('the attributed change', attributedChange.toJSON())
    t.assert(attributedChange.done().equals(delta.create().retain(11).insert('!', null, { insert: [] })))
    const unattributedChange = event.delta
    console.log('the UNattributed change', unattributedChange.toJSON())
    t.assert(unattributedChange.equals(delta.create().retain(5).insert('!')))
  })
  /**
   * Content now has different representations.
   * - The UNattributed representation renders the latest state, without history.
   * - The attributed representation renders the differences.
   *
   * Attributed: 'hello<delete> world</delete><insert>!</insert>'
   * UNattributed: 'world!'
   */
  // Apply a change to the attributed content
  ytype.applyDelta(delta.create().retain(11).insert('!'), am)
  // // Equivalent to applying a change to the UNattributed content:
  // ytype.applyDelta(delta.create().retain(5).insert('!'))
}