packages/node_modules/pouchdb-adapter-utils/src/processDocs.js

import { createError, MISSING_DOC, REV_CONFLICT } from 'pouchdb-errors';
import updateDoc from './updateDoc';
import {
  isDeleted,
  isLocalId,
  merge,
  winningRev as calculateWinningRev
} from 'pouchdb-merge';

function rootIsMissing(docInfo) {
  return docInfo.metadata.rev_tree[0].ids[1].status === 'missing';
}

function insertDoc(docInfo, resultsIdx, results, newEdits, wasDelete, writeDoc, callback) {
  // Cant insert new deleted documents
  var winningRev = calculateWinningRev(docInfo.metadata);
  var deleted = isDeleted(docInfo.metadata, winningRev);
  if (wasDelete && deleted) {
    results[resultsIdx] = createError(MISSING_DOC, 'deleted');
    return callback();
  }

  // 4712 - detect whether a new document was inserted with a _rev
  var inConflict = newEdits && rootIsMissing(docInfo);

  if (inConflict) {
    var err = createError(REV_CONFLICT);
    results[resultsIdx] = err;
    return callback();
  }

  var delta = deleted ? 0 : 1;

  writeDoc(docInfo, winningRev, deleted, deleted, false,
    delta, resultsIdx, callback);
}

function doWriteDocs(fetchedDocs, thisId, docs, results,
                       revLimit, writeDoc, newEdits, wasDelete, checkAllDocsDone) {
  var numDone = 0;

  function docWritten() {
    if (++numDone < docs.length) {
      nextDoc();
    } else {
      checkAllDocsDone();
    }
  }
  function nextDoc() {
    var value = docs[numDone];
    var currentDoc = value[0];
    var resultsIdx = value[1];

    if (fetchedDocs.has(thisId)) {
      updateDoc(revLimit, fetchedDocs.get(thisId), currentDoc, results,
        resultsIdx, docWritten, writeDoc, newEdits);
    } else {
      // Ensure stemming applies to new writes as well
      var merged = merge([], currentDoc.metadata.rev_tree[0], revLimit);
      currentDoc.metadata.rev_tree = merged.tree;
      currentDoc.stemmedRevs = merged.stemmedRevs || [];
      insertDoc(currentDoc, resultsIdx, results, newEdits, wasDelete, writeDoc, docWritten);
    }
  }
  nextDoc();
}

function processDocs(revLimit, docInfos, api, fetchedDocs, tx, results,
                     writeDoc, opts, overallCallback) {

  // Default to 1000 locally
  revLimit = revLimit || 1000;

  var newEdits = opts.new_edits;
  var wasDelete = 'was_delete' in opts;
  var idsToDocs = {};

  var docsDone = 0;
  var docsToDo = docInfos.length;

  function checkAllDocsDone() {
    if (++docsDone === docsToDo && overallCallback) {
      overallCallback();
    }
  }

  for (var i = 0, len = docInfos.length; i < len; i++) {
    var currentDoc = docInfos[i];
    if (currentDoc._id && isLocalId(currentDoc._id)) {
      var fun = currentDoc._deleted ? '_removeLocal' : '_putLocal';
      api[fun](currentDoc, {ctx: tx}, function (err, res) {
        results[i] = err || res;
        checkAllDocsDone();
      });
      continue;
    }

    var id = currentDoc.metadata.id;
    var key = '$' + id;
    var currentValue = idsToDocs[key];
    if (currentValue) {
      docsToDo--; // duplicate
      currentValue.push([currentDoc, i]);
    } else {
      idsToDocs[key] = [[currentDoc, i]];
    }
  }

  // in the case of new_edits, the user can provide multiple docs
  // with the same id. these need to be processed sequentially
  for (var thisKey in idsToDocs) {
    if (idsToDocs.hasOwnProperty(thisKey)) {
      var thisId = thisKey.substring(1); // remove leading '$'
      var docs = idsToDocs[thisKey];
      doWriteDocs(fetchedDocs, thisId, docs, results, revLimit, writeDoc,
        newEdits, wasDelete, checkAllDocsDone);
    }
  }
}

export default processDocs;