I have a problem bining UnderscoreJS and MongooseJS in NodeJS. I have a result of mongoose and I want filter a array

var __ = require("underscore"),
    platformInfo = __.findWhere(user.platforms, {"pId": platformId});

But pId inside user.platforms is a ObjectId and can't find. But if i make a each and pare like this all its OK:

__.each(user.platforms, function(platform){

                if(platform.pId.toString() == platformId){

                }

});

How i can find in findWhere method (one line, and cool) the same result? Thanks

I have a problem bining UnderscoreJS and MongooseJS in NodeJS. I have a result of mongoose and I want filter a array

var __ = require("underscore"),
    platformInfo = __.findWhere(user.platforms, {"pId": platformId});

But pId inside user.platforms is a ObjectId and can't find. But if i make a each and pare like this all its OK:

__.each(user.platforms, function(platform){

                if(platform.pId.toString() == platformId){

                }

});

How i can find in findWhere method (one line, and cool) the same result? Thanks

• javascript
• node.js
• mongodb
• mongoose
• underscore.js

4 Answers 4

Sadly mongodb ObjectId instances do not work properly with JavaScript's equality operators == or ===. You either need to use the provided method: objectId1.equals(objectId2) or ensure they are both converted to strings and then underscore or === will work.

platformInfo = _.filter(user.platforms, function (platform) {
  return platform.pId.toString() === platformId;
})

I tried to write a general function for that problem using underscore.js:

function findWhereObjectId(objs, p) {
    return _.find(objs, function(obj) {
        return _.some(_.keys(obj), function(key) {
            return (key == _.keys(p)[0] && obj[key].equals(p[key]));
        });
    });
};

You could now call findWhereObjectId(user.platforms, {"pId": platformId}) and it should give you the first match.

As mentioned before, mongodb ObjectId instances do not work properly with JavaScript's equality operators. However, there's another simpler solution for this problem: You could take your MongoDB result object and convert it to a string via JSON.stringify():

    var myString = JSON.stringify(MONGODB_RESULT);

After that you can convert that string back to an object via JSON.parse():

    var myObject = JSON.parse(myString);

You can now perform any Lodash/Underscore operation on that object.

Hope that helps!

You can use .toString after id of mongo response obbject For ex

_.findWhere(allMappingData, {_categoryId: catObj._id.toString() ,_contentId: content.contentId.toString()}));