Function replicate

lib/index-browser.js:9729–10264

(src, target, opts, returnValue, result)

}

function replicate(src, target, opts, returnValue, result) {
  var batches = [];               // list of batches to be processed
  var currentBatch;               // the batch currently being processed
  var pendingBatch = {
    seq: 0,
    changes: [],
    docs: []
  }; // next batch, not yet ready to be processed
  var writingCheckpoint = false;  // true while checkpoint is being written
  var changesCompleted = false;   // true when all changes received
  var replicationCompleted = false; // true when replication has completed
  // initial_last_seq is the state of the source db before
  // replication started, and it is _not_ updated during
  // replication or used anywhere else, as opposed to last_seq
  var initial_last_seq = 0;
  var last_seq = 0;
  var continuous = opts.continuous || opts.live || false;
  var batch_size = opts.batch_size || 100;
  var batches_limit = opts.batches_limit || 10;
  var style = opts.style || 'all_docs';
  var changesPending = false;     // true while src.changes is running
  var doc_ids = opts.doc_ids;
  var selector = opts.selector;
  var repId;
  var checkpointer;
  var changedDocs = [];
  // Like couchdb, every replication gets a unique session id
  var session = uuid$1();
  var taskId;

  result = result || {
    ok: true,
    start_time: new Date().toISOString(),
    docs_read: 0,
    docs_written: 0,
    doc_write_failures: 0,
    errors: []
  };

  var changesOpts = {};
  returnValue.ready(src, target);

  function initCheckpointer() {
    if (checkpointer) {
      return Promise.resolve();
    }
    return generateReplicationId(src, target, opts).then(function (res) {
      repId = res;

      var checkpointOpts = {};
      if (opts.checkpoint === false) {
        checkpointOpts = { writeSourceCheckpoint: false, writeTargetCheckpoint: false };
      } else if (opts.checkpoint === 'source') {
        checkpointOpts = { writeSourceCheckpoint: true, writeTargetCheckpoint: false };
      } else if (opts.checkpoint === 'target') {
        checkpointOpts = { writeSourceCheckpoint: false, writeTargetCheckpoint: true };
      } else {
        checkpointOpts = { writeSourceCheckpoint: true, writeTargetCheckpoint: true };