Removing an empty array from an object with JavaScript

Question

I have this JSON object myFilters :

{"filters":
      {"role":"","jobs":[]}
}

I can correctly remove the empty object from it with this function clean ( myFilters ):

function clean(obj) {
  for (var propName in obj) {
    if (
      obj[propName] === null ||
      obj[propName] === undefined ||
      obj[propName] === ""
    ) {
      delete obj[propName];
    }
  }

So now, my myFilters object becomes:

{"filters":
    { "jobs":[] }
}

How can I now remove the empty array and the key from my JSON object?

Answer 1

You should add one more condition like

function clean(obj) {
  for (var propName in obj) {
    if (
      obj[propName] === null ||
      obj[propName] === undefined ||
      obj[propName] === "" ||
      Array.isArray(obj[propName]) && obj[propName].length === 0
    ) {
      delete obj[propName];
    }
  }
}

Answer 2

You should check the type of property before check its value by the typeof

The jobs property is an object and you can check its value by its length . it is empty if its length equals to 0.

function clean(obj) {

    for (var propName in obj) {

        if (typeof (obj[propName]) == 'object') {

            if (obj[propName].length == 0) {
                delete obj[propName];
            }

        } else {

            if (
                obj[propName] === null ||
                obj[propName] === undefined ||
                obj[propName] === ""
            ) {
                delete obj[propName];
            }

        }
        
    }

}

Answer 3

I like Saveli Tomac's solution , so I upvoted that. Let me show you an additional shortening on the original solution also.

As it's been stated that you need to check 2 more things if you are looking for an empty array. So what about checking null , undefined and '' values easier?

 if (!undefined) { console.log('undefined needs to be deleted') }; if (!null) { console.log('null needs to be deleted') }; if (!'') { console.log(`'' needs to be deleted`) };

Checking Array.length if it has 0 value can be also shorter just like the following:

 const array1 = []; const array2 = [1,2,3]; if (!array1.length) { console.log('array1 has 0 length') }; if (!array2.length) { console.log('array2 has 0 length') };

So based on those code snippets you can have an additional shortening just like the following:

 // extended with other types for the demo let myObject = { "filters": { "role": "", "jobs": [], "nullValue": null, "undefinedIsHere": undefined, "arrayWithValue": [1,2,3], "stringValue": "hello", "numberishere": 123 } }; const clean = (obj) => { for (let propName in obj) { if ( !obj[propName] || Array.isArray(obj[propName]) && !obj[propName].length ) { delete obj[propName] }; } } clean(myObject.filters); console.log(myObject);

Or with a 1️⃣ liner:

 // extended with other types for the demo let myObject = { "filters": { "role": "", "jobs": [], "nullValue": null, "undefinedIsHere": undefined, "arrayWithValue": [1,2,3], "stringValue": "hello", "numberishere": 123 } }; const clean = (obj) => { Object.keys(obj).forEach(propName => (!obj[propName] || Array.isArray(obj[propName]) && !obj[propName].length) && delete obj[propName]); } clean(myObject.filters); console.log(myObject);

Read further here:

1. Array.isArray()
2. Array.length

I hope this helps!

Answer 4

Try this :

 var filterObj = { "filters": { "role": "", "jobs": [] } }; for (var i in filterObj) { for (var j in filterObj[i]) { if ((filterObj[i][j] === null) || (filterObj[i][j] === undefined) || (filterObj[i][j].length === 0)) { delete filterObj[i][j]; } } } console.log(filterObj);

Answer 5

It should be like this:

function clean(obj) {
  for (var propName in obj) {
    if (obj.hasOwnProperty(propName) && 
      obj[propName] === null ||
      obj[propName] === undefined ||
      obj[propName] === "" || 
      (Array.isArray(obj[propName]) && obj[propName].length <= 0)
    ) {
      delete obj[propName];
    }
  }
}

Answer 6

Saveli 's answer should work fine. Here's an alternative approach you can use to achieve the same result.

 const object = { "filters": { "role": "", "jobs": [], "foo": undefined, "baz": null, "bar": {}, "moreJobs": ['1', '2'] } } const result = { filters: Object.keys(object.filters).reduce((acc, key) => { if ( object.filters[key] !== null && object.filters[key] !== undefined && object.filters[key] !== '' && typeof object.filters[key] === 'object' && Object.keys(object.filters[key]).length > 0 ) { acc[key] = object.filters[key]; } return acc; }, {}) }; console.log(result);