Order array by value in NodeJS

Question

I am learning node and now I'm trying to order an array like this:

"lng" : [{
        "ES" : 5,
        "EN" : 3,
        "IT" : 4
    }]

(This is a part of a query result in MongoDB), I need to order the array by the number:

"ES" : 5,
"IT" : 4,      
"EN" : 3

I used sort() but this function orders the array alphabetically by the first parameter, but I need order by the second, I've tried a lot of things but without result.

Thank you for your help!

are you using mongoose? or mongodb native? please post your full query — Alex
– Alex, Commented Feb 20, 2015 at 10:59
Are you trying to sort the {"ES":5,"EN":3,"IT":4} JavaScript Object? If I remember correctly, JavaScript objects' key-value pairs don't have an "order". — Passerby
– Passerby, Commented Feb 20, 2015 at 11:04
Hi Alex, thanks for reply, I am using Mongoose. Each element of the collection is like that: { "_id" : ObjectId("54a15e7e3453b5741a6c7be0"), "name" : "Miguel", "lng" : { "ES" : 5, "EN" : 3, "IT" : 4 }, "email" : "[email protected]", "password" : "123123" } ...etc. And the query: db.users.find({ "lng.en" : {$lt : 5 } }) I want to get the users who have "EN" with level 1,2,3 or 4. Thank you — Miguel Haba
– Miguel Haba, Commented Feb 20, 2015 at 11:05
don't paste code in comments, update your question, and format the code please — Alex
– Alex, Commented Feb 20, 2015 at 11:11

NikitaBaksalyar · Accepted Answer · 2015-02-20 11:22:45Z

6

JavaScript has no ordered objects, so first you should transform your object to an array of this kind:

[
    { key: "ES", value: 5 },
    { key: "EN", value: 3 },
    { key: "IT", value: 4 }
]

And then sort by the value key.

You can easily do it as follows:

// ("mongoDbResult" is the variable with an object you get from MongoDB)
var result = mongoDbResult.lng;

result = Object.keys(result).map(function (key) {
  return { key: key, value: result[key] };
});

And then just sort by the value key:

result.sort(function (a, b) {
  return (a.value < b.value) ? -1 : 1;
});

As a result, you should get a sorted array in the result variable.

edited Feb 20, 2015 at 11:22

answered Feb 20, 2015 at 11:17

NikitaBaksalyar

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Comments

Miguel Haba · Accepted Answer · 2015-02-20 12:06:38Z

0

Thank you Nikita, adding the key and value the sort works perfectly, my problem now is make the query to get the results with specific key and value...

I can get the elements by the KEY:

db.users.find({"lng.key" : "ES"})

Or by the VALUE:

db.users.find({"lng.value" : 5})

But not the both at the same query :/

[EDIT]

I have find the solution, $elemMatch:

db.users.find({lng_array : {$elemMatch:{key:"ES", value:5}}})

edited Feb 20, 2015 at 12:06

answered Feb 20, 2015 at 11:51

Miguel Haba

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