CODEWITHSUNDEEP
javascriptsortingunderscore.js
Vikram Sethumadhavan
Vikram Sethumadhavan

Reputation: 117

underscorejs groupby and filter

I have an array of objects. I would like to groupby & filter(remove) the object, category which is undefined. Please refer the script below for more clarity :

arrayFlatten = [
      {
        area:"Digital",
        category:undefined,
        qId:"q11",
        qqId:"step1",
        type:"Reduce",
        val:1,
        userId:1,
        weightedAverage:0
      },
      {
        area:"Digital",
        category:"Analytics",
        qId:"q1",
        qqId:"step1",
        type:"Reduce",
        val:1,
        userId:1,
        weightedAverage:0
      },
      {
        area:"Digital",
        category:"Analytics",
        qId:"q1",
        qqId:"step2",
        type:"Reduce",
        val:1,
        userId:1,
        weightedAverage:0
      }
]

The command used to sort using group by 

var groupCategory = _.groupBy(arrayFlatten,'category');
console.log(groupCategory);

The expected result is supposed to look like:

arrayFlatten = [
          {
            area:"Digital",
            category:"Analytics",
            qId:"q1",
            qqId:"step1",
            type:"Reduce",
            val:1,
            userId:1,
            weightedAverage:0
          },
          {
            area:"Digital",
            category:"Analytics",
            qId:"q1",
            qqId:"step2",
            type:"Reduce",
            val:1,
            userId:1,
            weightedAverage:0
          }
    ]

Upvotes: 0

Views: 246

Answers (1)

Simon Brahan
Simon Brahan

Reputation: 2076

filteredArray = _.filter(
    arrayFlatten,
    function (obj) {
        return obj.category !== undefined;
    }
);

filteredArray will contain your array with no undefined categories.

You can also do this without underscore in most modern browsers, using Array.filter() described here: https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Array/filter

Upvotes: 1

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