How to group by on multiple items using underscore.js

Question

I have an array of objects with length 10000. I want to manipulate the data. can anyone help me.

This is how, my data looks like

[
        {
            "date": "Nov 24, 2015",
            "article_type": "Casual Shoes",
            "brand": "Puma",
            "realised_revenue": "596,882.3",
            "realised_quantity": "289"
        },
        {
            "date": "Nov 23, 2015",
            "article_type": "Casual Shoes",
            "brand": "Puma",
            "realised_revenue": "595,882.3",
            "realised_quantity": "288"
        },
        {
            "article_type": "Sports Shoes",
            "brand": "Puma",
            "date": "Nov 23, 2015",
            "realised_revenue": "394,195.9",
            "realised_quantity": "134"
        },
        {
            "article_type": "Sweatshirts",
            "brand": "Puma",
            "date": "Nov 23, 2015",
            "realised_revenue": "337,385.2",
            "realised_quantity": "191"
        }
    ]

This is how, I want to manipulate.

    [
{
    groupByRes:{"article_type": "Casual Shoes","brand": "Puma"},
    results:[
        {
            "date": "Nov 24, 2015",
            "article_type": "Casual Shoes",
            "brand": "Puma",
            "realised_revenue": "596,882.3",
            "realised_quantity": "289"
        },
        {
            "date": "Nov 23, 2015",
            "article_type": "Casual Shoes",
            "brand": "Puma",
            "realised_revenue": "595,882.3",
            "realised_quantity": "288"
        }
    ]
},
{
    groupByRes:{"article_type": "Sports Shoes","brand": "Puma"},
    results:[
        {
            "article_type": "Sports Shoes",
            "brand": "Puma",
            "date": "Nov 23, 2015",
            "realised_revenue": "394,195.9",
            "realised_quantity": "134"
        }
    ]
},
{
    groupByRes:{"article_type": "Sweatshirts,"brand": "Puma"},
    results:[
        {
            "article_type": "Sweatshirts",
            "brand": "Puma",
            "date": "Nov 23, 2015",
            "realised_revenue": "337,385.2",
            "realised_quantity": "191"
        }
    ]
}
 ]

I want to group by article_type and brand . can anyone help me.

Thanks

Answer 1

You can "cheat" by using _.groupBy() :

 var arr = [ { "date": "Nov 24, 2015", "article_type": "Casual Shoes", "brand": "Puma", "realised_revenue": "596,882.3", "realised_quantity": "289" }, { "date": "Nov 23, 2015", "article_type": "Casual Shoes", "brand": "Puma", "realised_revenue": "595,882.3", "realised_quantity": "288" }, { "date": "Nov 23, 2015", "article_type": "Casual Shoes", "brand": "Not Puma", "realised_revenue": "595,882.3", "realised_quantity": "288" }, { "article_type": "Sports Shoes", "brand": "Puma", "date": "Nov 23, 2015", "realised_revenue": "394,195.9", "realised_quantity": "134" }, { "article_type": "Sweatshirts", "brand": "Puma", "date": "Nov 23, 2015", "realised_revenue": "337,385.2", "realised_quantity": "191" } ]; var out = _(arr).groupBy(function (obj) { // return a stringified object containing the type and the brand return JSON.stringify({ "article_type": obj.article_type, "brand": obj.brand }); }).map(function(value, key) { return { // parse back the key which is a stringified object groupByRes: JSON.parse(key), results: value } }).value(); out = JSON.stringify(out, null, 3); console.log(out); document.write('<pre>' + out + '</pre>'); 

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