How to remove empty,null, undefined values from array within object using underscore

Question

I want to remove all the keys associated with null, I tried with _.filter, _.compact, _.reject, but nothing works for me, am using latest version of underscore 1.8.3

This is what I tried:

_.reject(Obj,function (value) {
    return value===null;
})

_.compact(Obj)

Object:

    var Obj =  {
  "pCon": [
    {
      "abc": null,
      "def": null,
      "ghi": {
        "content": "abc"
      }
    },
    {
      "abc": null,
      "def": {
        imgURL: "test.png"
      },
      "ghi": null
    },
    {
      "abc": {
        "key": "001"
      },
      "def": null,
      "ghi": null
    }
  ]
}

Why with underscore? You can use array_filter() from phpjs.org and it works perfectly fine with few lines of code and it will be more readable than mixing all this underscore functions. — Marcos Pérez Gude
– Marcos Pérez Gude, Commented Feb 24, 2016 at 14:36
what do you mean by empty? empty strings? and should undefined properties deleted as well? — Nina Scholz
– Nina Scholz, Commented Feb 24, 2016 at 14:52

Nina Scholz · Accepted Answer · 2016-02-24 18:33:41Z

2

A solution in plain Javascript in a recursive style.

function deleteNull(o) {
    if (typeof o === 'object') {
        Object.keys(o).forEach(function (k) {
            if (o[k] === null) { // or undefined or '' ...?
                delete o[k];
                return;
            }
            deleteNull(o[k]);
        });
    }
}

var object = { "pCon": [{ "abc": null, "def": null, "ghi": { "content": "abc" } }, { "abc": null, "def": { imgURL: "test.png" }, "ghi": null }, { "abc": { "key": "001" }, "def": null, "ghi": null }] };

deleteNull(object);
document.write('<pre>' + JSON.stringify(object, 0, 4) + '</pre>');

edited Feb 24, 2016 at 18:33

answered Feb 24, 2016 at 14:47

Nina Scholz

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Comments

Cagri Tacyildiz · Accepted Answer · 2016-02-24 14:32:48Z

0

 for (var i in Obj["pCon"]) {
  if (Obj["pCon"][i]["abc"] === null || Obj["pCon"][i]["abc"] === undefined) {
  // test[i] === undefined is probably not very useful here
    delete Obj["pCon"][i]["abc"];
  }
  if (Obj["pCon"][i]["def"] === null || Obj["pCon"][i]["def"] === undefined) {
  // test[i] === undefined is probably not very useful here
    delete Obj["pCon"][i]["def"];
  }
  if (Obj["pCon"][i]["ghi"] === null || Obj["pCon"][i]["ghi"] === undefined) {
  // test[i] === undefined is probably not very useful here
    delete Obj["pCon"][i]["ghi"];
  }
}

it works in jsfiddle https://jsfiddle.net/3wd7dmex/1/

answered Feb 24, 2016 at 14:32

Cagri Tacyildiz

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Comments

Ashwin Sadeep · Accepted Answer · 2016-02-26 11:58:26Z

This is the solution using underscore. Please note that this will not recursively go deeper into the structure like Nina's solution does. But you can extend this to mirror that behaviour if need be.

var obj = {
  "pCon": [{
    "abc": null,
    "def": null,
    "ghi": {
      "content": "abc"
    }
  }, {
    "abc": null,
    "def": {
      imgURL: "test.png"
    },
    "ghi": null
  }, {
    "abc": {
      "key": "001"
    },
    "def": null,
    "ghi": null
  }]
};
var result = _.chain(obj).map(function(value, key) {
  value = _.map(value, function(singleObj) {
    return _.pick(singleObj, _.identity) // pick the keys where values are non empty
  });
  return [key, value];
}).object().value();

document.write('<pre>' + JSON.stringify(result, 0, 4) + '</pre>');

<script src="https://cdnjs.cloudflare.com/ajax/libs/underscore.js/1.8.3/underscore-min.js"></script>

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