对象内部数组的Collection.find（）

Question

I have a Meteor app that has a collection of chat groups. Each document in this collection looks like this:

{groupname: 'name', whitelist: ['person1', 'person2', 'person3'], messages:['message1', 'message2', 'message3']}

To show each person with an account what groups they are part of, I need a page with a list of those groups they're allowed in. How can I use a find() command to return all of the documents whose whitelist array contains the user's name?

Answer 1

Something like this:

ChatGroups.find({whitelist: Meteor.user().username});

This assumes that username is the property you want to match against. You don't need to do anything special to search within an array in this case - mongo will do the correct thing (compare username to each element of each whitelist and return those documents that match).

Answer 2

To search in MongoDB by array items - use $in operator:

ChatGroups.find({
   whitelist: {
      $in: [Meteor.user()._id]
   }
});

Reference: Comparison Query Operators > $in