function documentPatch()

in backend/new.js [1564:1595]

• 29 lines of code
• 12 McCabe index (conditional complexity)

function documentPatch(docState) {
  for (let col of docState.blocks[0].columns) col.decoder.reset()
  let propState = {}, docOp = null, blockIndex = 0
  let patches = {_root: {objectId: '_root', type: 'map', props: {}}}
  let lastObjActor = null, lastObjCtr = null, objectId = '_root', elemVisible = false, listIndex = 0

  while (true) {
    ({ docOp, blockIndex } = readNextDocOp(docState, blockIndex))
    if (docOp === null) break
    if (docOp[objActorIdx] !== lastObjActor || docOp[objCtrIdx] !== lastObjCtr) {
      objectId = `${docOp[objCtrIdx]}@${docState.actorIds[docOp[objActorIdx]]}`
      lastObjActor = docOp[objActorIdx]
      lastObjCtr = docOp[objCtrIdx]
      propState = {}
      listIndex = 0
      elemVisible = false
    }

    if (docOp[insertIdx] && elemVisible) {
      elemVisible = false
      listIndex++
    }
    if (docOp[succNumIdx] === 0) elemVisible = true
    if (docOp[idCtrIdx] > docState.maxOp) docState.maxOp = docOp[idCtrIdx]
    for (let i = 0; i < docOp[succNumIdx]; i++) {
      if (docOp[succCtrIdx][i] > docState.maxOp) docState.maxOp = docOp[succCtrIdx][i]
    }

    updatePatchProperty(patches, null, objectId, docOp, docState, propState, listIndex, docOp[succNumIdx])
  }
  return patches._root
}