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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