Function changes

lib/index-browser.js:5673–5863

(opts, api, dbName, idb)

}

function changes(opts, api, dbName, idb) {
  opts = clone(opts);

  if (opts.continuous) {
    var id = dbName + ':' + uuid$1();
    changesHandler.addListener(dbName, id, api, opts);
    changesHandler.notify(dbName);
    return {
      cancel: function () {
        changesHandler.removeListener(dbName, id);
      }
    };
  }

  var docIds = opts.doc_ids && new Set(opts.doc_ids);

  opts.since = opts.since || 0;
  var lastSeq = opts.since;

  var limit = 'limit' in opts ? opts.limit : -1;
  if (limit === 0) {
    limit = 1; // per CouchDB _changes spec
  }

  var results = [];
  var numResults = 0;
  var filter = filterChange(opts);
  var docIdsToMetadata = new Map();

  var txn;
  var bySeqStore;
  var docStore;
  var docIdRevIndex;

  function onBatch(batchKeys, batchValues, cursor) {
    if (!cursor || !batchKeys.length) { // done
      return;
    }

    var winningDocs = new Array(batchKeys.length);
    var metadatas = new Array(batchKeys.length);

    function processMetadataAndWinningDoc(metadata, winningDoc) {
      var change = opts.processChange(winningDoc, metadata, opts);
      lastSeq = change.seq = metadata.seq;

      var filtered = filter(change);
      if (typeof filtered === 'object') { // anything but true/false indicates error
        return Promise.reject(filtered);
      }

      if (!filtered) {
        return Promise.resolve();
      }
      numResults++;
      if (opts.return_docs) {
        results.push(change);
      }