remove false values from nested objects recursively

removeFalseValuesRecurse.js

import _isObjectLike from 'lodash/isObjectLike';
import _size from 'lodash/size';

function removeEmptyValuesRecursively(obj) {
  return removeEmptyValues(obj);

  function isFalsy(val) {
    // return true, if val is empty [], empty {} or null

    return !_isObjectLike(val) ? val === null : _size(val) <= 0;
  }

  function removeEmptyValues(data) {
    if (_isObjectLike(data)) {
      const result = Object.entries(data).reduce((res, [key, value]) => {
        const newValue = removeEmptyValues(value);

        if (!isFalsy(newValue)) {
          res[key] = newValue;
        }

        return res;
      }, Array.isArray(data) ? [] : {});

      return isFalsy(result) ? undefined : result;
    }

    return isFalsy(data) ? undefined : data;
  }
}


// removeEmptyValuesRecursively({a: { b: { d: {} } }) => undefined
// removeEmptyValuesRecursively({a: { b: { d: {} c: 1 } }) => {a : { b : { c: 1} } }

Thanks for this @kra3. I tried this and made a small modification because I noticed that when there is a null value in an array, it will become:

[ <1 empty item>, { my: object } ]

And when converted into JSON, it just becomes null again because there is an empty element in the array. Instead of saving the next non-falsy value to the same index, I modified it so that it pushes the element into the array thereby eliminating empty elements.

          if (Array.isArray(res)) {
            res.push(newValue)
          } else {
            res[key] = newValue
          }