I have ask another question, but someone close that question. I really need this answer. That's why I asking another question.

I have a object like following. I have to remove that empty string filed from nested object and also from nested array. How can I remove that.

const obj = {
  name: 'Red Boy',
  price: '350',
  originalPrice: '', // Empty string field
  stock: 20,
  category: {
    name: '', // Empty String field
    subCategory: { name: ''} // Empty String filed 
  },
  weight: '90kg',
  dimensions: {
    width: '50cm',
    height: '', // Empty string filed
    length: '70cm'
  },
  suitable: [
     { name: 'Yoga' },
     { name: '' }, // Empty String filed
     { name: 'Winter' }
  ],
  additionalInfo: [
     { field: 'closure', value: 'Button' },
     { field: 'collar', value: ''} // Empty String Field 
  ]
}

In this hybrid object type you can see some sub-object and also some sub-array. You can also see some field that are not contain any value.(I ment out that filed).

Actually I need to remove that filed. How can I remove that empty string field from above hybrid object type.

Thank you..

My Expected result-

{
  name: 'Red Boy',
  price: '350',
  // Removed
  stock: 20,
  category: {
    name: '', // Empty String field
    // Removed
  },
  weight: '90kg',
  dimensions: {
    width: '50cm',
    // Removed
    length: '70cm'
  },
  suitable: [
     { name: 'Yoga' },
     //Removed
     { name: 'Winter' }
  ],
  additionalInfo: [
     { field: 'closure', value: 'Button' },
     { field: 'collar', //Removed }
     // Here If this two filed is empty then should remove the whole object
     { field: '', value: '' }
     // Then should remove whole '{ field: '', value: '' }'
  ]
}

I have ask another question, but someone close that question. I really need this answer. That's why I asking another question.

I have a object like following. I have to remove that empty string filed from nested object and also from nested array. How can I remove that.

const obj = {
  name: 'Red Boy',
  price: '350',
  originalPrice: '', // Empty string field
  stock: 20,
  category: {
    name: '', // Empty String field
    subCategory: { name: ''} // Empty String filed 
  },
  weight: '90kg',
  dimensions: {
    width: '50cm',
    height: '', // Empty string filed
    length: '70cm'
  },
  suitable: [
     { name: 'Yoga' },
     { name: '' }, // Empty String filed
     { name: 'Winter' }
  ],
  additionalInfo: [
     { field: 'closure', value: 'Button' },
     { field: 'collar', value: ''} // Empty String Field 
  ]
}

In this hybrid object type you can see some sub-object and also some sub-array. You can also see some field that are not contain any value.(I ment out that filed).

Actually I need to remove that filed. How can I remove that empty string field from above hybrid object type.

Thank you..

My Expected result-

{
  name: 'Red Boy',
  price: '350',
  // Removed
  stock: 20,
  category: {
    name: '', // Empty String field
    // Removed
  },
  weight: '90kg',
  dimensions: {
    width: '50cm',
    // Removed
    length: '70cm'
  },
  suitable: [
     { name: 'Yoga' },
     //Removed
     { name: 'Winter' }
  ],
  additionalInfo: [
     { field: 'closure', value: 'Button' },
     { field: 'collar', //Removed }
     // Here If this two filed is empty then should remove the whole object
     { field: '', value: '' }
     // Then should remove whole '{ field: '', value: '' }'
  ]
}

• javascript

4 Answers 4

To achieve this, we need to implement a recursive function to remove all empty string in all nested arrays and objects.

function rec(obj){
    for(let key of Object.keys(obj)){
        if (obj[key] === ''){
            delete obj[key];
        }
        else if (typeof obj[key] === 'object'){
            obj[key] = rec(obj[key]);
            if (Object.keys(obj[key]).length === 0 ) delete obj[key];
        }
    }
    return Array.isArray(obj) ? obj.filter(val => val) : obj;
}

Also, please note that it's not purely hybrid. Because Array is special type of Object.

const obj = {
  name: 'Red Boy',
  price: '350',
  originalPrice: '', // Empty string field
  stock: 20,
  category: {
    name: '', // Empty String field
    subCategory: { name: ''} // Empty String filed 
  },
  weight: '90kg',
  dimensions: {
    width: '50cm',
    height: '', // Empty string filed
    length: '70cm'
  },
  suitable: [
     { name: 'Yoga' },
     { name: '' }, // Empty String filed
     { name: 'Winter' }
  ],
  additionalInfo: [
     { field: 'closure', value: 'Button' },
     { field: 'collar', value: ''} // Empty String Field 
  ]
}

function removeEmptyString(object) {
    Object
        .entries(object)
        .forEach(([key, value]) => {
            if (value && typeof value === 'object')
                removeEmptyString(value);
            if (value && 
                typeof value === 'object' && 
                !Object.keys(value).length || 
                value === null || 
                value === undefined ||
                value.length === 0
            ) {
                if (Array.isArray(object))
                    object.splice(key, 1);
                else
                    delete object[key];
            }
        });
    return object;
}

console.log(removeEmptyString(obj))

Here's an immutable way to remove non-empty values from an object, with the added capability of normalising object's inside of arrays:

const normaliseObject = (obj) =>
  Object.fromEntries(
    Object.entries(obj)
      .filter(([_, value]) => value !== '' && value !== null)
      .map(([key, value]) => (typeof value === 'object' ? [key, normalise(value)] : [key, value])),
  )

// If an element in an array is an object, normalise that too
const normaliseArray = (arr) => arr.map(value => (typeof value === 'object' ? normalise(value) : value))

/**
 * Normalise any object to remove keys whose values are falsey
 * @param obj Object to be normalised
 * @returns Normalised object where falsey values are removed
 */
const normalise = (obj) => {
  return Array.isArray(obj) ? normaliseArray(obj) : normaliseObject(obj)
}

I have used recursion to filter out the empty string, empty object or empty array present deep inside the nested structure.

This function also removes such objects and their nested objects with no properties.

Note: It will also work if the provided initial value is any other thing then object like array or string

var obj={name:"Red Boy",price:"350",originalPrice:"",stock:20,category:{name:"",subCategory:{name:""}},weight:"90kg",dimensions:{width:"50cm",height:"",length:"70cm"},suitable:[{name:"Yoga"},{name:""},{name:"Winter"}],additionalInfo:[{field:"closure",value:"Button"},{field:"collar",value:""}]};

function filt(a) {
  if (typeof a === 'string') return a !== '';
  //if it is a string, then it must not be empty
  else if (Array.isArray(a)) return a.length !== 0
  //if it an arra, then it must have some item
  else if (a instanceof Object) return Object.keys(a).length !== 0;
  //if it is an object, then it must have some property
  return a !== null && a !== undefined
  //else it must not be null or undefined
}

function rec(obj) {
  if (Array.isArray(obj)) {
    //if an value is an array
    return obj.map((a) => rec(a)).filter((a) => filt(a)) //recurse the child first of each value in the array
    //then filter out the value which are either null, empty, undefined or have length 0
  } else if (obj instanceof Object) {
    //if value is an object
    var d = Object.entries(obj).map((a) => ([a[0], rec(a[1])])).filter((a) => filt(a[1]));
    //map through the object.entries and reassign the values to the keys by recursing over the value to filter out the nested inside irrelevant value
    return Object.fromEntries(d)
    //convert the map into object and return
  } else if (typeof obj === 'string') return obj !== '' ? obj : null
  //f it is a string, it must not be empty else return null
  return obj !== null && obj !== undefined ? obj : null
  //else it must not be null or undefined
}

console.log("For object",rec(obj))
console.log("For Array",rec([{
  name: "Yoga"
}, {
  name: ""
}, {
  name: "Winter"
}]))