Group by/order by On JSON data using javascript/jquery

Question

I have a JSON data and I need to do something like group by and i asked this question before here but i am not getting any satisfied answer so this time i would like to explain more in depth.

First, Can anybody explain me difference between groupby and orderby in javascript as in sql we do required aggregate function in order to use group by. But I don't want anything like aggregate function. Here I provide a very sample JSON data and Output that I was looking for.

All author names should be sortby alphanumeric order.

JSON data:

var myObject = {
    "Apps": [
        {
            "Name": "app1",
            "id": "1",
            "groups": [
                {
                    "id": "1",
                    "name": "test group 1",
                    "category": "clinical note",
                    "author": "RRP"
                }, {
                    "id": "2",
                    "name": "test group 2",
                    "category": "clinical image",
                    "author": "LKP"
                }, {
                    "id": "3",
                    "name": "test group 3",
                    "category": "clinical document",
                    "author": "RRP"
                }, {
                    "id": "4",
                    "name": "test group 4",
                    "category": "clinical note",
                    "author": "John"
                }
            ]
        }
    ]
}

Expected output:

John
  4 testgroup4 clinicalnote 
RRP
  1 testgroup1  clinicalnote
  3 testgroup3  clinicaldocument
LKP
  2 testgroup2 clinicalimage

Any idea/suggestion/direction/thought would be great help.

There is no groupby / orderby in JavaScript, or do you use a library? If you're talking about SQL, please provide your query. — Bergi, Jun 18 '12 at 20:54
Thanks for reply.There is no sql.I have only JSON data.I know there is no groupby/orderby in javascript. Is there any way i can achive this goal. No i can not use a library as we developed our inhouse lang. I know library does not matter but due to company policy i can not use third party javascript library. — ravi, Jun 18 '12 at 20:57

score 3 · Accepted Answer · answered Feb 09 '14 at 07:55

3

You can do that easily with Underscore.js:

_.chain(myObject.Apps[0].groups).sortBy("author").groupBy("author").value();

Outputs a JSON object:

{
 "John":[{"id":"4","name":"test group 4","category":"clinical note","author":"John"}],
 "LKP":[{"id":"2","name":"test group 2","category":"clinical image","author":"LKP"}],
 "RRP":[{"id":"1","name":"test group 1","category":"clinical note","author":"RRP"},{"id":"3","name":"test group 3","category":"clinical document","author":"RRP"}]
}

answered Feb 09 '14 at 07:55

Andrejs

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What if i want the new object to be formated as follows ?: {username: "Jhon", userinfo: [{...}]} ? – Q_ro Feb 21 '14 at 16:31
1

@Q_ro then you can post process the resulting object, for example with http://underscorejs.org/#pairs or `map` but that's already a different question – Andrejs Feb 21 '14 at 19:52

Vivin Paliath · Answer 2 · 2012-06-18T21:07:25.697

There is no built-in "group by" or "order by" in Javascript for this scenario. You're going to have to do this manually. Something like this might help:

var groups = myObject.Apps[0].groups;
var authors = {};
var authorNames = [];

for(var i = 0; i < groups.length; i++) {
    var group = groups[i];    

    if(typeof authors[group.author] === "undefined") {
        authors[group.author] = [];
        authorNames.push(group.author);
        authorNames.sort();
    }

    authors[group.author].push({
        id: group.id,
        name: group.name,
        category: group.category
    });       
}

Usually in associative arrays you don't really care about the order of the keys and while iterating the order is usually not guaranteed. What I'm doing here is maintaining a separate array of names in sorted order. I can then iterate over that array and use those values to grab the associated object out of the associative array.

Check out the fiddle.

Thanks Vivin.I will do sort first and than pass whole object for gropu by so in this way i will get exact order.I guess your solution will work out. — ravi, Jun 19 '12 at 18:41

David Lemon · Answer 3 · 2019-01-11T13:43:26.277

Use first class functions to create generic group by key reducers and a sorters. I will take the reducer from a previous answer of mine. That way you can sort and group by any key you like, in a similar way that you would do in SQL.

const groupBy = key => (result,current) => {
  const item = Object.assign({},current);
  if (typeof result[current[key]] == 'undefined'){
    result[current[key]] = [item];
  }else{
    result[current[key]].push(item);
  }
  return result;
};

const stringSortBy = key => (a,b) => {
   const sa = a[key];
   const sb = b[key];
   return sa < sb ? -1 : +(sa > sb);
};

const myObject = {
    "Apps": [
        {
            "Name": "app1",
            "id": "1",
            "groups": [
                {
                    "id": "1",
                    "name": "test group 1",
                    "category": "clinical note",
                    "author": "RRP"
                }, {
                    "id": "2",
                    "name": "test group 2",
                    "category": "clinical image",
                    "author": "LKP"
                }, {
                    "id": "3",
                    "name": "test group 3",
                    "category": "clinical document",
                    "author": "RRP"
                }, {
                    "id": "4",
                    "name": "test group 4",
                    "category": "clinical note",
                    "author": "John"
                }
            ]
        }
    ]
}

const categories = myObject.Apps[0].groups.reduce(groupBy('category'),{});
console.log(categories);
const sorted = myObject.Apps[0].groups.sort(stringSortBy('author'));
console.log(sorted);

Group by/order by On JSON data using javascript/jquery

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