mongodb - Meteor 对集合有独特的查询吗？

Question

我想返回我的集合中的不同字段。我知道这些是 docs for mongo operators ，但我对查询语言不够熟悉，不知道这是否可行？

Meteor.publish("distinctCollection", function() {
    return Collection.find({ ... }, fields: { "myField": 1 });
});

Answer 1

Collection.find({}).distinct('myField', true);

要使用，请将以下内容放入[project]/client/lib/a.js:

LocalCollection.Cursor.prototype.distinct = function (key,random) {
  var self = this;

  if (self.db_objects === null)
    self.db_objects = self._getRawObjects(true);
  if (random)
    self.db_objects = _.shuffle(self.db_objects);
  if (self.reactive)
    self._markAsReactive({ordered: true,
                          added: true,
                          removed: true,
                          changed: true,
                          moved: true});
  var res = {};
  _.each(self.db_objects,function(value){

    if(!res[value[key]]){
        res[value[key]] = value;
    }
  });
  return _.values(res);
};