How to remove empty values from object using lodash

Question

I have an object with several properties and I would like to remove objects/nested objects that are empty, using lodash. What is the best way to do this?

Let template = {
      node: "test",
      representation: {
        range: { }
      },
      transmit: {
        timeMs: 0
      }
    };

to

template = {
      node: "test",
      transmit: {
        timeMs: 0
      }
    };

I tried something like this, but I am lost.

Utils.removeEmptyObjects = function(obj) {
  return _.transform(obj, function(o, v, k) {
    if (typeof v === 'object') {
      o[k] = _.removeEmptyObjects(v);
    } else if (!_.isEmpty(v)) {
      o[k] = v;
    }
  });
};
_.mixin({
  'removeEmptyObjects': Utils.removeEmptyObjects
});

Answer 1

You can achieve this through several steps:

1. Use pickBy() to pick object key-values, using the isObject() predicate.

2. Use mapValues() to recursively call removeEmptyObjects(), note that it would only invoke this function with objects.

3. Remove all empty objects that are found after the mapValues() using omitBy() with an isEmpty() predicate.

4. Assign all primitive values from the object all over again using assign() for assignment, and omitBy() with an isObject() predicate.

---

function removeEmptyObjects(obj) {
  return _(obj)
    .pickBy(_.isObject) // pick objects only
    .mapValues(removeEmptyObjects) // call only for object values
    .omitBy(_.isEmpty) // remove all empty objects
    .assign(_.omitBy(obj, _.isObject)) // assign back primitive values
    .value();
}

function removeEmptyObjects(obj) {
  return _(obj)
    .pickBy(_.isObject)
    .mapValues(removeEmptyObjects)
    .omitBy(_.isEmpty)
    .assign(_.omitBy(obj, _.isObject))
    .value();
}

_.mixin({
  removeEmptyObjects: removeEmptyObjects
});

var template = {
  node: "test",
  representation: {
    range: {}
  },
  transmit: {
    timeMs: 0
  }
};

var result = _.removeEmptyObjects(template);

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

<script src="https://cdn.jsdelivr.net/lodash/4.13.1/lodash.min.js"></script>

Answer 2

To remove undefined, null, and empty string from an object with no nested objects

_.omitBy(object, (v) => _.isUndefined(v) || _.isNull(v) || v === '');

for nested objects, you can make a recursive function doing that

It will remove empty Objects, empty array, null, undefined, empty strings with any level...

removeEmpty(obj) {
        let finalObj = {};
        Object.keys(obj).forEach((key) => {
            if (obj[key] && typeof obj[key] === 'object') {
                const nestedObj = removeEmpty(obj[key]);
                if (Object.keys(nestedObj).length) {
                    finalObj[key] = nestedObj;
                }
            } else if (obj[key] !== '' && obj[key] !== undefined && obj[key] !== null) {
                finalObj[key] = obj[key];
            }
        });
        return finalObj;
    }

UPDATE 11-4-2022

Based on @RahulSoni comment I just fixed converting of arrays to objects. Now everything should be handled. Please let me know if you have any other comments

removeEmpty(obj) {
    const finalObj = {};
    Object.keys(obj).forEach((key) => {
      if (obj[key] && typeof obj[key] === 'object' && !Array.isArray(obj[key])) {
        const nestedObj = this.removeEmpty(obj[key]);
        if (Object.keys(nestedObj).length) {
          finalObj[key] = nestedObj;
        }
      } else if (Array.isArray(obj[key])) {
        if (obj[key].length) {
          obj[key].forEach((x) => {
            const nestedObj = this.removeEmpty(x);
            if (Object.keys(nestedObj).length) {
              finalObj[key] = finalObj[key] ? [...finalObj[key], nestedObj] : [nestedObj];
            }
          });
        }
      } else if (obj[key] !== '' && obj[key] !== undefined && obj[key] !== null) {
        finalObj[key] = obj[key];
      }
    });
    return finalObj;
  }

Example:

   const obj = {
            a: '',
            aa: null,
            aaa: undefined,
            aaaa: 'aaaa',
            aaaaa: 0,
            aaaaaa: 1,
            aaaaaaa: 2,
            aaaaaaaa: true,
            aaaaaaaaa: false,
            emptyObj: {},
            emptyArray: [],
            array: [
                {
                    a: '',
                    aa: null,
                    aaa: undefined,
                    aaaa: 'aaaa',
                    aaaaa: 0,
                    aaaaaa: 1,
                    aaaaaaa: 2,
                    aaaaaaaa: true,
                    aaaaaaaaa: false,
                    emptyObj: {},
                    emptyArray: [],
                    obj: {
                        a: '',
                        aa: null,
                        aaa: undefined,
                        aaaa: 'aaaa',
                        aaaaa: 0,
                        aaaaaa: 1,
                        aaaaaaa: 2,
                        aaaaaaaa: true,
                        aaaaaaaaa: false,
                        emptyObj: {},
                        emptyArray: [],
                    },
                },
                {
                    a: '',
                    aa: null,
                    aaa: undefined,
                    aaaa: 'aaaa',
                    aaaaa: 0,
                    aaaaaa: 1,
                    aaaaaaa: 2,
                    aaaaaaaa: true,
                    aaaaaaaaa: false,
                    emptyObj: {},
                    emptyArray: [],
                    obj: {
                        a: '',
                        aa: null,
                        aaa: undefined,
                        aaaa: 'aaaa',
                        aaaaa: 0,
                        aaaaaa: 1,
                        aaaaaaa: 2,
                        aaaaaaaa: true,
                        aaaaaaaaa: false,
                        emptyObj: {},
                        emptyArray: [],
                    },
                },
            ],
            b: {
                a: '',
                aa: null,
                aaa: undefined,
                aaaa: 'aaaa',
                aaaaa: 0,
                aaaaaa: 1,
                aaaaaaa: 2,
                aaaaaaaa: true,
                aaaaaaaaa: false,
                emptyObj: {},
                emptyArray: [],
                c: {
                    a: '',
                    aa: null,
                    aaa: undefined,
                    aaaa: 'aaaa',
                    aaaaa: 0,
                    aaaaaa: 1,
                    aaaaaaa: 2,
                    aaaaaaaa: true,
                    aaaaaaaaa: false,
                    emptyObj: {},
                    emptyArray: [],
                },
            },
        };

        const finalObj = removeEmpty(obj);
        console.log('finalObj After remove', finalObj);