bulk insert into minimongo

bulkinsert.js

export function insertBulk(collection, documents) {
  if(collection) {
    const last = _.last(documents);
    _.each(documents, item => {
      if(_.isObject(item)) {
        if (EJSON.equals(item._id, last._id)) {
          collection.upsert({ _id: last._id}, item);
        }
        else {
          if(_.isObject(item._id)) {
            //If ObjectID is used, we must use _str to get its stirng representation
            //Or else .toString() will called, which will return a different type
            //of mapping than .insert/.update functions
            const string = item._id.toHexString();
            collection._collection._docs._map[string] = item;
          }
          else
            //Using string value as ID
            collection._collection._docs._map[item._id] = item;
        }
      }
    });
  }
}